/*
 * libdivsufsort
 * Copyright (c) 2003-2008 Yuta Mori All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person
 * obtaining a copy of this software and associated documentation
 * files (the "Software"), to deal in the Software without
 * restriction, including without limitation the rights to use,
 * copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following
 * conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
 * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
 * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
 * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 * OTHER DEALINGS IN THE SOFTWARE.
 */

#ifndef INCLUDED_SDSL_DIVSUFSORT
#define INCLUDED_SDSL_DIVSUFSORT

#include <algorithm>
#include <assert.h>
#include <stdio.h>
#include <inttypes.h>

#ifdef _OPENMP
# include <omp.h>
#endif

namespace sdsl {

#if !defined(UINT8_MAX)
# define UINT8_MAX (255)
#endif

#define ALPHABET_SIZE (256)
#define BUCKET_A_SIZE (ALPHABET_SIZE)
#define BUCKET_B_SIZE (ALPHABET_SIZE * ALPHABET_SIZE)
#define SS_INSERTIONSORT_THRESHOLD (8)
#define SS_BLOCKSIZE (1024)
#define SS_MISORT_STACKSIZE (16)
#define TR_INSERTIONSORT_THRESHOLD (8)

template <typename saidx_t>
struct libdivsufsort_config;

template <>
struct libdivsufsort_config<int32_t>
{
    static constexpr uint64_t TR_STACKSIZE = 64;
    static constexpr uint64_t SS_SMERGE_STACKSIZE = 32;
};

template <>
struct libdivsufsort_config<int64_t>
{
    static constexpr uint64_t TR_STACKSIZE = 96;
    static constexpr uint64_t SS_SMERGE_STACKSIZE = 64;
};

#define BUCKET_A(_c0) bucket_A[(_c0)]
#if ALPHABET_SIZE == 256
#define BUCKET_B(_c0, _c1) (bucket_B[((_c1) << 8) | (_c0)])
#define BUCKET_BSTAR(_c0, _c1) (bucket_B[((_c0) << 8) | (_c1)])
#else
#define BUCKET_B(_c0, _c1) (bucket_B[(_c1) * ALPHABET_SIZE + (_c0)])
#define BUCKET_BSTAR(_c0, _c1) (bucket_B[(_c0) * ALPHABET_SIZE + (_c1)])
#endif

#define STACK_PUSH(_a, _b, _c, _d)\
 do {\
   stack[ssize].a = (_a), stack[ssize].b = (_b),\
   stack[ssize].c = (_c), stack[ssize++].d = (_d);\
 } while(0)
#define STACK_PUSH5(_a, _b, _c, _d, _e)\
 do {\
   stack[ssize].a = (_a), stack[ssize].b = (_b),\
   stack[ssize].c = (_c), stack[ssize].d = (_d), stack[ssize++].e = (_e);\
 } while(0)
#define STACK_POP(_a, _b, _c, _d)\
 do {\
   assert(0 <= ssize);\
   if(ssize == 0) { return; }\
   (_a) = stack[--ssize].a, (_b) = stack[ssize].b,\
   (_c) = stack[ssize].c, (_d) = stack[ssize].d;\
 } while(0)
#define STACK_POP5(_a, _b, _c, _d, _e)\
 do {\
   assert(0 <= ssize);\
   if(ssize == 0) { return; }\
   (_a) = stack[--ssize].a, (_b) = stack[ssize].b,\
   (_c) = stack[ssize].c, (_d) = stack[ssize].d, (_e) = stack[ssize].e;\
 } while(0)

static const int32_t lg_table[256]= {
 -1,0,1,1,2,2,2,2,3,3,3,3,3,3,3,3,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,
  5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,
  6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,
  6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,
  7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
  7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
  7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
  7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7
};

#if (SS_BLOCKSIZE == 0) || (SS_INSERTIONSORT_THRESHOLD < SS_BLOCKSIZE)

inline int32_t ss_ilg(int32_t n) {
#if SS_BLOCKSIZE == 0
  return (n & 0xffff0000) ?
          ((n & 0xff000000) ?
            24 + lg_table[(n >> 24) & 0xff] :
            16 + lg_table[(n >> 16) & 0xff]) :
          ((n & 0x0000ff00) ?
             8 + lg_table[(n >>  8) & 0xff] :
             0 + lg_table[(n >>  0) & 0xff]);
#elif SS_BLOCKSIZE < 256
  return lg_table[n];
#else
  return (n & 0xff00) ?
          8 + lg_table[(n >> 8) & 0xff] :
          0 + lg_table[(n >> 0) & 0xff];
#endif
}

inline int32_t ss_ilg(int64_t n) {
#if SS_BLOCKSIZE == 0
  return (n >> 32) ?
          ((n >> 48) ?
            ((n >> 56) ?
              56 + lg_table[(n >> 56) & 0xff] :
              48 + lg_table[(n >> 48) & 0xff]) :
            ((n >> 40) ?
              40 + lg_table[(n >> 40) & 0xff] :
              32 + lg_table[(n >> 32) & 0xff])) :
          ((n & 0xffff0000) ?
            ((n & 0xff000000) ?
              24 + lg_table[(n >> 24) & 0xff] :
              16 + lg_table[(n >> 16) & 0xff]) :
            ((n & 0x0000ff00) ?
               8 + lg_table[(n >>  8) & 0xff] :
               0 + lg_table[(n >>  0) & 0xff]));
#elif SS_BLOCKSIZE < 256
  return lg_table[n];
#else
  return (n & 0xff00) ?
          8 + lg_table[(n >> 8) & 0xff] :
          0 + lg_table[(n >> 0) & 0xff];
#endif
}

#endif /* (SS_BLOCKSIZE == 0) || (SS_INSERTIONSORT_THRESHOLD < SS_BLOCKSIZE) */

#if SS_BLOCKSIZE != 0

static const int32_t sqq_table[256] = {
  0,  16,  22,  27,  32,  35,  39,  42,  45,  48,  50,  53,  55,  57,  59,  61,
 64,  65,  67,  69,  71,  73,  75,  76,  78,  80,  81,  83,  84,  86,  87,  89,
 90,  91,  93,  94,  96,  97,  98,  99, 101, 102, 103, 104, 106, 107, 108, 109,
110, 112, 113, 114, 115, 116, 117, 118, 119, 120, 121, 122, 123, 124, 125, 126,
128, 128, 129, 130, 131, 132, 133, 134, 135, 136, 137, 138, 139, 140, 141, 142,
143, 144, 144, 145, 146, 147, 148, 149, 150, 150, 151, 152, 153, 154, 155, 155,
156, 157, 158, 159, 160, 160, 161, 162, 163, 163, 164, 165, 166, 167, 167, 168,
169, 170, 170, 171, 172, 173, 173, 174, 175, 176, 176, 177, 178, 178, 179, 180,
181, 181, 182, 183, 183, 184, 185, 185, 186, 187, 187, 188, 189, 189, 190, 191,
192, 192, 193, 193, 194, 195, 195, 196, 197, 197, 198, 199, 199, 200, 201, 201,
202, 203, 203, 204, 204, 205, 206, 206, 207, 208, 208, 209, 209, 210, 211, 211,
212, 212, 213, 214, 214, 215, 215, 216, 217, 217, 218, 218, 219, 219, 220, 221,
221, 222, 222, 223, 224, 224, 225, 225, 226, 226, 227, 227, 228, 229, 229, 230,
230, 231, 231, 232, 232, 233, 234, 234, 235, 235, 236, 236, 237, 237, 238, 238,
239, 240, 240, 241, 241, 242, 242, 243, 243, 244, 244, 245, 245, 246, 246, 247,
247, 248, 248, 249, 249, 250, 250, 251, 251, 252, 252, 253, 253, 254, 254, 255
};

template <typename saidx_t>
inline saidx_t ss_isqrt(saidx_t x) {
  saidx_t y, e;

  if(x >= (SS_BLOCKSIZE * SS_BLOCKSIZE)) { return SS_BLOCKSIZE; }
  e = (x & 0xffff0000) ?
        ((x & 0xff000000) ?
          24 + lg_table[(x >> 24) & 0xff] :
          16 + lg_table[(x >> 16) & 0xff]) :
        ((x & 0x0000ff00) ?
           8 + lg_table[(x >>  8) & 0xff] :
           0 + lg_table[(x >>  0) & 0xff]);

  if(e >= 16) {
    y = sqq_table[x >> ((e - 6) - (e & 1))] << ((e >> 1) - 7);
    if(e >= 24) { y = (y + 1 + x / y) >> 1; }
    y = (y + 1 + x / y) >> 1;
  } else if(e >= 8) {
    y = (sqq_table[x >> ((e - 6) - (e & 1))] >> (7 - (e >> 1))) + 1;
  } else {
    return sqq_table[x] >> 4;
  }

  return (x < (y * y)) ? y - 1 : y;
}

#endif /* SS_BLOCKSIZE != 0 */

/* Compares two suffixes. */
template <typename saidx_t>
inline int32_t ss_compare(const uint8_t *T, const saidx_t *p1, const saidx_t *p2, saidx_t depth) {
  const uint8_t *U1, *U2, *U1n, *U2n;

  for(U1 = T + depth + *p1,
      U2 = T + depth + *p2,
      U1n = T + *(p1 + 1) + 2,
      U2n = T + *(p2 + 1) + 2;
      (U1 < U1n) && (U2 < U2n) && (*U1 == *U2);
      ++U1, ++U2) {
  }

  return U1 < U1n ?
        (U2 < U2n ? *U1 - *U2 : 1) :
        (U2 < U2n ? -1 : 0);
}

#if (SS_BLOCKSIZE != 1) && (SS_INSERTIONSORT_THRESHOLD != 1)

/* Insertionsort for small size groups */
template <typename saidx_t>
inline void ss_insertionsort(const uint8_t *T, const saidx_t *PA, saidx_t *first, saidx_t *last, saidx_t depth) {
  saidx_t *i, *j;
  saidx_t t;
  int32_t r;

  for(i = last - 2; first <= i; --i) {
    for(t = *i, j = i + 1; 0 < (r = ss_compare(T, PA + t, PA + *j, depth));) {
      do { *(j - 1) = *j; } while((++j < last) && (*j < 0));
      if(last <= j) { break; }
    }
    if(r == 0) { *j = ~*j; }
    *(j - 1) = t;
  }
}

#endif /* (SS_BLOCKSIZE != 1) && (SS_INSERTIONSORT_THRESHOLD != 1) */

#if (SS_BLOCKSIZE == 0) || (SS_INSERTIONSORT_THRESHOLD < SS_BLOCKSIZE)

template <typename saidx_t>
inline void ss_fixdown(const uint8_t *Td, const saidx_t *PA, saidx_t *SA, saidx_t i, saidx_t size) {
  saidx_t j, k;
  saidx_t v;
  int32_t c, d, e;

  for(v = SA[i], c = Td[PA[v]]; (j = 2 * i + 1) < size; SA[i] = SA[k], i = k) {
    d = Td[PA[SA[k = j++]]];
    if(d < (e = Td[PA[SA[j]]])) { k = j; d = e; }
    if(d <= c) { break; }
  }
  SA[i] = v;
}

/* Simple top-down heapsort. */
template <typename saidx_t>
inline void ss_heapsort(const uint8_t *Td, const saidx_t *PA, saidx_t *SA, saidx_t size) {
  saidx_t i, m;
  saidx_t t;

  m = size;
  if((size % 2) == 0) {
    m--;
    if(Td[PA[SA[m / 2]]] < Td[PA[SA[m]]]) { std::swap(SA[m], SA[m / 2]); }
  }

  for(i = m / 2 - 1; 0 <= i; --i) { ss_fixdown(Td, PA, SA, i, m); }
  if((size % 2) == 0) { std::swap(SA[0], SA[m]); ss_fixdown(Td, PA, SA, (saidx_t)0, m); }
  for(i = m - 1; 0 < i; --i) {
    t = SA[0], SA[0] = SA[i];
    ss_fixdown(Td, PA, SA, (saidx_t)0, i);
    SA[i] = t;
  }
}

/* Returns the median of three elements. */
template <typename saidx_t>
inline saidx_t * ss_median3(const uint8_t *Td, const saidx_t *PA, saidx_t *v1, saidx_t *v2, saidx_t *v3) {
  if(Td[PA[*v1]] > Td[PA[*v2]]) { std::swap(v1, v2); }
  if(Td[PA[*v2]] > Td[PA[*v3]]) {
    if(Td[PA[*v1]] > Td[PA[*v3]]) { return v1; }
    else { return v3; }
  }
  return v2;
}

/* Returns the median of five elements. */
template <typename saidx_t>
inline saidx_t * ss_median5(const uint8_t *Td, const saidx_t *PA,
                            saidx_t *v1, saidx_t *v2, saidx_t *v3, saidx_t *v4, saidx_t *v5) {
  if(Td[PA[*v2]] > Td[PA[*v3]]) { std::swap(v2, v3); }
  if(Td[PA[*v4]] > Td[PA[*v5]]) { std::swap(v4, v5); }
  if(Td[PA[*v2]] > Td[PA[*v4]]) { std::swap(v2, v4); std::swap(v3, v5); }
  if(Td[PA[*v1]] > Td[PA[*v3]]) { std::swap(v1, v3); }
  if(Td[PA[*v1]] > Td[PA[*v4]]) { std::swap(v1, v4); std::swap(v3, v5); }
  if(Td[PA[*v3]] > Td[PA[*v4]]) { return v4; }
  return v3;
}

/* Returns the pivot element. */
template <typename saidx_t>
inline saidx_t * ss_pivot(const uint8_t *Td, const saidx_t *PA, saidx_t *first, saidx_t *last) {
  saidx_t *middle;
  saidx_t t;

  t = last - first;
  middle = first + t / 2;

  if(t <= 512) {
    if(t <= 32) {
      return ss_median3(Td, PA, first, middle, last - 1);
    } else {
      t >>= 2;
      return ss_median5(Td, PA, first, first + t, middle, last - 1 - t, last - 1);
    }
  }
  t >>= 3;
  first  = ss_median3(Td, PA, first, first + t, first + (t << 1));
  middle = ss_median3(Td, PA, middle - t, middle, middle + t);
  last   = ss_median3(Td, PA, last - 1 - (t << 1), last - 1 - t, last - 1);
  return ss_median3(Td, PA, first, middle, last);
}

/* Binary partition for substrings. */
template <typename saidx_t>
inline saidx_t * ss_partition(const saidx_t *PA, saidx_t *first, saidx_t *last, saidx_t depth) {
  saidx_t *a, *b;
  saidx_t t;
  for(a = first - 1, b = last;;) {
    for(; (++a < b) && ((PA[*a] + depth) >= (PA[*a + 1] + 1));) { *a = ~*a; }
    for(; (a < --b) && ((PA[*b] + depth) <  (PA[*b + 1] + 1));) { }
    if(b <= a) { break; }
    t = ~*b;
    *b = *a;
    *a = t;
  }
  if(first < a) { *first = ~*first; }
  return a;
}

/* Multikey introsort for medium size groups. */
template <typename saidx_t>
inline void ss_mintrosort(const uint8_t *T, const saidx_t *PA, saidx_t *first, saidx_t *last, saidx_t depth) {
  struct { saidx_t *a, *b, c; int32_t d; } stack[SS_MISORT_STACKSIZE];
  const uint8_t *Td;
  saidx_t *a, *b, *c, *d, *e, *f;
  saidx_t s, t;
  int32_t ssize;
  int32_t limit;
  int32_t v, x = 0;

  for(ssize = 0, limit = ss_ilg((saidx_t)(last - first));;) {

    if((last - first) <= SS_INSERTIONSORT_THRESHOLD) {
#if 1 < SS_INSERTIONSORT_THRESHOLD
      if(1 < (last - first)) { ss_insertionsort(T, PA, first, last, depth); }
#endif
      STACK_POP(first, last, depth, limit);
      continue;
    }

    Td = T + depth;
    if(limit-- == 0) { ss_heapsort(Td, PA, first, (saidx_t)(last - first)); }
    if(limit < 0) {
      for(a = first + 1, v = Td[PA[*first]]; a < last; ++a) {
        if((x = Td[PA[*a]]) != v) {
          if(1 < (a - first)) { break; }
          v = x;
          first = a;
        }
      }
      if(Td[PA[*first] - 1] < v) {
        first = ss_partition(PA, first, a, depth);
      }
      if((a - first) <= (last - a)) {
        if(1 < (a - first)) {
          STACK_PUSH(a, last, depth, -1);
          last = a, depth += 1, limit = ss_ilg((saidx_t)(a - first));
        } else {
          first = a, limit = -1;
        }
      } else {
        if(1 < (last - a)) {
          STACK_PUSH(first, a, depth + 1, ss_ilg((saidx_t)(a - first)));
          first = a, limit = -1;
        } else {
          last = a, depth += 1, limit = ss_ilg((saidx_t)(a - first));
        }
      }
      continue;
    }

    /* choose pivot */
    a = ss_pivot(Td, PA, first, last);
    v = Td[PA[*a]];
    std::swap(*first, *a);

    /* partition */
    for(b = first; (++b < last) && ((x = Td[PA[*b]]) == v);) { }
    if(((a = b) < last) && (x < v)) {
      for(; (++b < last) && ((x = Td[PA[*b]]) <= v);) {
        if(x == v) { std::swap(*b, *a); ++a; }
      }
    }
    for(c = last; (b < --c) && ((x = Td[PA[*c]]) == v);) { }
    if((b < (d = c)) && (x > v)) {
      for(; (b < --c) && ((x = Td[PA[*c]]) >= v);) {
        if(x == v) { std::swap(*c, *d); --d; }
      }
    }
    for(; b < c;) {
      std::swap(*b, *c);
      for(; (++b < c) && ((x = Td[PA[*b]]) <= v);) {
        if(x == v) { std::swap(*b, *a); ++a; }
      }
      for(; (b < --c) && ((x = Td[PA[*c]]) >= v);) {
        if(x == v) { std::swap(*c, *d); --d; }
      }
    }

    if(a <= d) {
      c = b - 1;

      if((s = a - first) > (t = b - a)) { s = t; }
      for(e = first, f = b - s; 0 < s; --s, ++e, ++f) { std::swap(*e, *f); }
      if((s = d - c) > (t = last - d - 1)) { s = t; }
      for(e = b, f = last - s; 0 < s; --s, ++e, ++f) { std::swap(*e, *f); }

      a = first + (b - a), c = last - (d - c);
      b = (v <= Td[PA[*a] - 1]) ? a : ss_partition(PA, a, c, depth);

      if((a - first) <= (last - c)) {
        if((last - c) <= (c - b)) {
          STACK_PUSH(b, c, depth + 1, ss_ilg((saidx_t)(c - b)));
          STACK_PUSH(c, last, depth, limit);
          last = a;
        } else if((a - first) <= (c - b)) {
          STACK_PUSH(c, last, depth, limit);
          STACK_PUSH(b, c, depth + 1, ss_ilg((saidx_t)(c - b)));
          last = a;
        } else {
          STACK_PUSH(c, last, depth, limit);
          STACK_PUSH(first, a, depth, limit);
          first = b, last = c, depth += 1, limit = ss_ilg((saidx_t)(c - b));
        }
      } else {
        if((a - first) <= (c - b)) {
          STACK_PUSH(b, c, depth + 1, ss_ilg((saidx_t)(c - b)));
          STACK_PUSH(first, a, depth, limit);
          first = c;
        } else if((last - c) <= (c - b)) {
          STACK_PUSH(first, a, depth, limit);
          STACK_PUSH(b, c, depth + 1, ss_ilg((saidx_t)(c - b)));
          first = c;
        } else {
          STACK_PUSH(first, a, depth, limit);
          STACK_PUSH(c, last, depth, limit);
          first = b, last = c, depth += 1, limit = ss_ilg((saidx_t)(c - b));
        }
      }
    } else {
      limit += 1;
      if(Td[PA[*first] - 1] < v) {
        first = ss_partition(PA, first, last, depth);
        limit = ss_ilg((saidx_t)(last - first));
      }
      depth += 1;
    }
  }
}

#endif /* (SS_BLOCKSIZE == 0) || (SS_INSERTIONSORT_THRESHOLD < SS_BLOCKSIZE) */

#if SS_BLOCKSIZE != 0

template <typename saidx_t>
inline void ss_blockswap(saidx_t *a, saidx_t *b, saidx_t n) {
  saidx_t t;
  for(; 0 < n; --n, ++a, ++b) {
    t = *a, *a = *b, *b = t;
  }
}

template <typename saidx_t>
inline void ss_rotate(saidx_t *first, saidx_t *middle, saidx_t *last) {
  saidx_t *a, *b, t;
  saidx_t l, r;
  l = middle - first, r = last - middle;
  for(; (0 < l) && (0 < r);) {
    if(l == r) { ss_blockswap(first, middle, l); break; }
    if(l < r) {
      a = last - 1, b = middle - 1;
      t = *a;
      do {
        *a-- = *b, *b-- = *a;
        if(b < first) {
          *a = t;
          last = a;
          if((r -= l + 1) <= l) { break; }
          a -= 1, b = middle - 1;
          t = *a;
        }
      } while(1);
    } else {
      a = first, b = middle;
      t = *a;
      do {
        *a++ = *b, *b++ = *a;
        if(last <= b) {
          *a = t;
          first = a + 1;
          if((l -= r + 1) <= r) { break; }
          a += 1, b = middle;
          t = *a;
        }
      } while(1);
    }
  }
}

template <typename saidx_t>
inline void ss_inplacemerge(const uint8_t *T, const saidx_t *PA, saidx_t *first, saidx_t *middle, saidx_t *last,
                            saidx_t depth) {
  const saidx_t *p;
  saidx_t *a, *b;
  saidx_t len, half;
  int32_t q, r;
  int32_t x;

  for(;;) {
    if(*(last - 1) < 0) { x = 1; p = PA + ~*(last - 1); }
    else                { x = 0; p = PA +  *(last - 1); }
    for(a = first, len = middle - first, half = len >> 1, r = -1;
        0 < len;
        len = half, half >>= 1) {
      b = a + half;
      q = ss_compare(T, PA + ((0 <= *b) ? *b : ~*b), p, depth);
      if(q < 0) {
        a = b + 1;
        half -= (len & 1) ^ 1;
      } else {
        r = q;
      }
    }
    if(a < middle) {
      if(r == 0) { *a = ~*a; }
      ss_rotate(a, middle, last);
      last -= middle - a;
      middle = a;
      if(first == middle) { break; }
    }
    --last;
    if(x != 0) { while(*--last < 0) { } }
    if(middle == last) { break; }
  }
}

/* Merge-forward with internal buffer. */
template <typename saidx_t>
inline void ss_mergeforward(const uint8_t *T, const saidx_t *PA, saidx_t *first, saidx_t *middle, saidx_t *last,
                            saidx_t *buf, saidx_t depth) {
  saidx_t *a, *b, *c, *bufend;
  saidx_t t;
  int32_t r;

  bufend = buf + (middle - first) - 1;
  ss_blockswap(buf, first, (saidx_t)(middle - first));

  for(t = *(a = first), b = buf, c = middle;;) {
    r = ss_compare(T, PA + *b, PA + *c, depth);
    if(r < 0) {
      do {
        *a++ = *b;
        if(bufend <= b) { *bufend = t; return; }
        *b++ = *a;
      } while(*b < 0);
    } else if(r > 0) {
      do {
        *a++ = *c, *c++ = *a;
        if(last <= c) {
          while(b < bufend) { *a++ = *b, *b++ = *a; }
          *a = *b, *b = t;
          return;
        }
      } while(*c < 0);
    } else {
      *c = ~*c;
      do {
        *a++ = *b;
        if(bufend <= b) { *bufend = t; return; }
        *b++ = *a;
      } while(*b < 0);

      do {
        *a++ = *c, *c++ = *a;
        if(last <= c) {
          while(b < bufend) { *a++ = *b, *b++ = *a; }
          *a = *b, *b = t;
          return;
        }
      } while(*c < 0);
    }
  }
}

/* Merge-backward with internal buffer. */
template <typename saidx_t>
inline void ss_mergebackward(const uint8_t *T, const saidx_t *PA, saidx_t *first, saidx_t *middle, saidx_t *last,
                             saidx_t *buf, saidx_t depth) {
  const saidx_t *p1, *p2;
  saidx_t *a, *b, *c, *bufend;
  saidx_t t;
  int32_t r;
  int32_t x;

  bufend = buf + (last - middle) - 1;
  ss_blockswap(buf, middle, (saidx_t)(last - middle));

  x = 0;
  if(*bufend < 0)       { p1 = PA + ~*bufend; x |= 1; }
  else                  { p1 = PA +  *bufend; }
  if(*(middle - 1) < 0) { p2 = PA + ~*(middle - 1); x |= 2; }
  else                  { p2 = PA +  *(middle - 1); }
  for(t = *(a = last - 1), b = bufend, c = middle - 1;;) {
    r = ss_compare(T, p1, p2, depth);
    if(0 < r) {
      if(x & 1) { do { *a-- = *b, *b-- = *a; } while(*b < 0); x ^= 1; }
      *a-- = *b;
      if(b <= buf) { *buf = t; break; }
      *b-- = *a;
      if(*b < 0) { p1 = PA + ~*b; x |= 1; }
      else       { p1 = PA +  *b; }
    } else if(r < 0) {
      if(x & 2) { do { *a-- = *c, *c-- = *a; } while(*c < 0); x ^= 2; }
      *a-- = *c, *c-- = *a;
      if(c < first) {
        while(buf < b) { *a-- = *b, *b-- = *a; }
        *a = *b, *b = t;
        break;
      }
      if(*c < 0) { p2 = PA + ~*c; x |= 2; }
      else       { p2 = PA +  *c; }
    } else {
      if(x & 1) { do { *a-- = *b, *b-- = *a; } while(*b < 0); x ^= 1; }
      *a-- = ~*b;
      if(b <= buf) { *buf = t; break; }
      *b-- = *a;
      if(x & 2) { do { *a-- = *c, *c-- = *a; } while(*c < 0); x ^= 2; }
      *a-- = *c, *c-- = *a;
      if(c < first) {
        while(buf < b) { *a-- = *b, *b-- = *a; }
        *a = *b, *b = t;
        break;
      }
      if(*b < 0) { p1 = PA + ~*b; x |= 1; }
      else       { p1 = PA +  *b; }
      if(*c < 0) { p2 = PA + ~*c; x |= 2; }
      else       { p2 = PA +  *c; }
    }
  }
}

/* D&C based merge. */
template <typename saidx_t>
inline void ss_swapmerge(const uint8_t *T, const saidx_t *PA, saidx_t *first, saidx_t *middle, saidx_t *last,
                         saidx_t *buf, saidx_t bufsize, saidx_t depth) {
#define GETIDX(a) ((0 <= (a)) ? (a) : (~(a)))
#define MERGE_CHECK(a, b, c)\
  do {\
    if(((c) & 1) ||\
       (((c) & 2) && (ss_compare(T, PA + GETIDX(*((a) - 1)), PA + *(a), depth) == 0))) {\
      *(a) = ~*(a);\
    }\
    if(((c) & 4) && ((ss_compare(T, PA + GETIDX(*((b) - 1)), PA + *(b), depth) == 0))) {\
      *(b) = ~*(b);\
    }\
  } while(0)
  struct { saidx_t *a, *b, *c; int32_t d; } stack[libdivsufsort_config<saidx_t>::SS_SMERGE_STACKSIZE];
  saidx_t *l, *r, *lm, *rm;
  saidx_t m, len, half;
  int32_t ssize;
  int32_t check, next;

  for(check = 0, ssize = 0;;) {
    if((last - middle) <= bufsize) {
      if((first < middle) && (middle < last)) {
        ss_mergebackward(T, PA, first, middle, last, buf, depth);
      }
      MERGE_CHECK(first, last, check);
      STACK_POP(first, middle, last, check);
      continue;
    }

    if((middle - first) <= bufsize) {
      if(first < middle) {
        ss_mergeforward(T, PA, first, middle, last, buf, depth);
      }
      MERGE_CHECK(first, last, check);
      STACK_POP(first, middle, last, check);
      continue;
    }

    for(m = 0, len = std::min(middle - first, last - middle), half = len >> 1;
        0 < len;
        len = half, half >>= 1) {
      if(ss_compare(T, PA + GETIDX(*(middle + m + half)),
                       PA + GETIDX(*(middle - m - half - 1)), depth) < 0) {
        m += half + 1;
        half -= (len & 1) ^ 1;
      }
    }

    if(0 < m) {
      lm = middle - m, rm = middle + m;
      ss_blockswap(lm, middle, m);
      l = r = middle, next = 0;
      if(rm < last) {
        if(*rm < 0) {
          *rm = ~*rm;
          if(first < lm) { for(; *--l < 0;) { } next |= 4; }
          next |= 1;
        } else if(first < lm) {
          for(; *r < 0; ++r) { }
          next |= 2;
        }
      }

      if((l - first) <= (last - r)) {
        STACK_PUSH(r, rm, last, (next & 3) | (check & 4));
        middle = lm, last = l, check = (check & 3) | (next & 4);
      } else {
        if((next & 2) && (r == middle)) { next ^= 6; }
        STACK_PUSH(first, lm, l, (check & 3) | (next & 4));
        first = r, middle = rm, check = (next & 3) | (check & 4);
      }
    } else {
      if(ss_compare(T, PA + GETIDX(*(middle - 1)), PA + *middle, depth) == 0) {
        *middle = ~*middle;
      }
      MERGE_CHECK(first, last, check);
      STACK_POP(first, middle, last, check);
    }
  }
}

#endif /* SS_BLOCKSIZE != 0 */

/*- Function -*/

/* Substring sort */
template <typename saidx_t>
void
sssort(const uint8_t *T, const saidx_t *PA,
       saidx_t *first, saidx_t *last,
       saidx_t *buf, saidx_t bufsize,
       saidx_t depth, saidx_t n, int32_t lastsuffix) {
  saidx_t *a;
#if SS_BLOCKSIZE != 0
  saidx_t *b, *middle, *curbuf;
  saidx_t j, k, curbufsize, limit;
#endif
  saidx_t i;

  if(lastsuffix != 0) { ++first; }

#if SS_BLOCKSIZE == 0
  ss_mintrosort(T, PA, first, last, depth);
#else
  if((bufsize < SS_BLOCKSIZE) &&
      (bufsize < (last - first)) &&
      (bufsize < (limit = ss_isqrt(last - first)))) {
    if(SS_BLOCKSIZE < limit) { limit = SS_BLOCKSIZE; }
    buf = middle = last - limit, bufsize = limit;
  } else {
    middle = last, limit = 0;
  }
  for(a = first, i = 0; SS_BLOCKSIZE < (middle - a); a += SS_BLOCKSIZE, ++i) {
#if SS_INSERTIONSORT_THRESHOLD < SS_BLOCKSIZE
    ss_mintrosort(T, PA, a, a + SS_BLOCKSIZE, depth);
#elif 1 < SS_BLOCKSIZE
    ss_insertionsort(T, PA, a, a + SS_BLOCKSIZE, depth);
#endif
    curbufsize = last - (a + SS_BLOCKSIZE);
    curbuf = a + SS_BLOCKSIZE;
    if(curbufsize <= bufsize) { curbufsize = bufsize, curbuf = buf; }
    for(b = a, k = SS_BLOCKSIZE, j = i; j & 1; b -= k, k <<= 1, j >>= 1) {
      ss_swapmerge(T, PA, b - k, b, b + k, curbuf, curbufsize, depth);
    }
  }
#if SS_INSERTIONSORT_THRESHOLD < SS_BLOCKSIZE
  ss_mintrosort(T, PA, a, middle, depth);
#elif 1 < SS_BLOCKSIZE
  ss_insertionsort(T, PA, a, middle, depth);
#endif
  for(k = SS_BLOCKSIZE; i != 0; k <<= 1, i >>= 1) {
    if(i & 1) {
      ss_swapmerge(T, PA, a - k, a, middle, buf, bufsize, depth);
      a -= k;
    }
  }
  if(limit != 0) {
#if SS_INSERTIONSORT_THRESHOLD < SS_BLOCKSIZE
    ss_mintrosort(T, PA, middle, last, depth);
#elif 1 < SS_BLOCKSIZE
    ss_insertionsort(T, PA, middle, last, depth);
#endif
    ss_inplacemerge(T, PA, first, middle, last, depth);
  }
#endif

  if(lastsuffix != 0) {
    /* Insert last type B* suffix. */
    saidx_t PAi[2]; PAi[0] = PA[*(first - 1)], PAi[1] = n - 2;
    for(a = first, i = *(first - 1);
        (a < last) && ((*a < 0) || (0 < ss_compare(T, &(PAi[0]), PA + *a, depth)));
        ++a) {
      *(a - 1) = *a;
    }
    *(a - 1) = i;
  }
}

inline int32_t tr_ilg(int32_t n) {
  return (n & 0xffff0000) ?
          ((n & 0xff000000) ?
            24 + lg_table[(n >> 24) & 0xff] :
            16 + lg_table[(n >> 16) & 0xff]) :
          ((n & 0x0000ff00) ?
             8 + lg_table[(n >>  8) & 0xff] :
             0 + lg_table[(n >>  0) & 0xff]);
}

inline int32_t tr_ilg(int64_t n) {
  return (n >> 32) ?
          ((n >> 48) ?
            ((n >> 56) ?
              56 + lg_table[(n >> 56) & 0xff] :
              48 + lg_table[(n >> 48) & 0xff]) :
            ((n >> 40) ?
              40 + lg_table[(n >> 40) & 0xff] :
              32 + lg_table[(n >> 32) & 0xff])) :
          ((n & 0xffff0000) ?
            ((n & 0xff000000) ?
              24 + lg_table[(n >> 24) & 0xff] :
              16 + lg_table[(n >> 16) & 0xff]) :
            ((n & 0x0000ff00) ?
               8 + lg_table[(n >>  8) & 0xff] :
               0 + lg_table[(n >>  0) & 0xff]));
}

/* Simple insertionsort for small size groups. */
template <typename saidx_t>
inline void tr_insertionsort(const saidx_t *ISAd, saidx_t *first, saidx_t *last) {
  saidx_t *a, *b;
  saidx_t t, r;

  for(a = first + 1; a < last; ++a) {
    for(t = *a, b = a - 1; 0 > (r = ISAd[t] - ISAd[*b]);) {
      do { *(b + 1) = *b; } while((first <= --b) && (*b < 0));
      if(b < first) { break; }
    }
    if(r == 0) { *b = ~*b; }
    *(b + 1) = t;
  }
}

template <typename saidx_t>
inline void tr_fixdown(const saidx_t *ISAd, saidx_t *SA, saidx_t i, saidx_t size) {
  saidx_t j, k;
  saidx_t v;
  saidx_t c, d, e;

  for(v = SA[i], c = ISAd[v]; (j = 2 * i + 1) < size; SA[i] = SA[k], i = k) {
    d = ISAd[SA[k = j++]];
    if(d < (e = ISAd[SA[j]])) { k = j; d = e; }
    if(d <= c) { break; }
  }
  SA[i] = v;
}

/* Simple top-down heapsort. */
template <typename saidx_t>
inline void tr_heapsort(const saidx_t *ISAd, saidx_t *SA, saidx_t size) {
  saidx_t i, m;
  saidx_t t;

  m = size;
  if((size % 2) == 0) {
    m--;
    if(ISAd[SA[m / 2]] < ISAd[SA[m]]) { std::swap(SA[m], SA[m / 2]); }
  }

  for(i = m / 2 - 1; 0 <= i; --i) { tr_fixdown(ISAd, SA, i, m); }
  if((size % 2) == 0) { std::swap(SA[0], SA[m]); tr_fixdown(ISAd, SA, (saidx_t)0, m); }
  for(i = m - 1; 0 < i; --i) {
    t = SA[0], SA[0] = SA[i];
    tr_fixdown(ISAd, SA, (saidx_t)0, i);
    SA[i] = t;
  }
}

/* Returns the median of three elements. */
template <typename saidx_t>
inline saidx_t * tr_median3(const saidx_t *ISAd, saidx_t *v1, saidx_t *v2, saidx_t *v3) {
  if(ISAd[*v1] > ISAd[*v2]) { std::swap(v1, v2); }
  if(ISAd[*v2] > ISAd[*v3]) {
    if(ISAd[*v1] > ISAd[*v3]) { return v1; }
    else { return v3; }
  }
  return v2;
}

/* Returns the median of five elements. */
template <typename saidx_t>
inline saidx_t * tr_median5(const saidx_t *ISAd, saidx_t *v1, saidx_t *v2, saidx_t *v3, saidx_t *v4, saidx_t *v5) {
  if(ISAd[*v2] > ISAd[*v3]) { std::swap(v2, v3); }
  if(ISAd[*v4] > ISAd[*v5]) { std::swap(v4, v5); }
  if(ISAd[*v2] > ISAd[*v4]) { std::swap(v2, v4); std::swap(v3, v5); }
  if(ISAd[*v1] > ISAd[*v3]) { std::swap(v1, v3); }
  if(ISAd[*v1] > ISAd[*v4]) { std::swap(v1, v4); std::swap(v3, v5); }
  if(ISAd[*v3] > ISAd[*v4]) { return v4; }
  return v3;
}

/* Returns the pivot element. */
template <typename saidx_t>
inline saidx_t * tr_pivot(const saidx_t *ISAd, saidx_t *first, saidx_t *last) {
  saidx_t *middle;
  saidx_t t;

  t = last - first;
  middle = first + t / 2;

  if(t <= 512) {
    if(t <= 32) {
      return tr_median3(ISAd, first, middle, last - 1);
    } else {
      t >>= 2;
      return tr_median5(ISAd, first, first + t, middle, last - 1 - t, last - 1);
    }
  }
  t >>= 3;
  first  = tr_median3(ISAd, first, first + t, first + (t << 1));
  middle = tr_median3(ISAd, middle - t, middle, middle + t);
  last   = tr_median3(ISAd, last - 1 - (t << 1), last - 1 - t, last - 1);
  return tr_median3(ISAd, first, middle, last);
}

template <typename saidx_t>
struct _trbudget_t {
  saidx_t chance;
  saidx_t remain;
  saidx_t incval;
  saidx_t count;
};

template <typename saidx_t>
using trbudget_t = struct _trbudget_t<saidx_t>;
// typedef struct _trbudget_t trbudget_t;

template <typename saidx_t>
inline void trbudget_init(trbudget_t<saidx_t> *budget, saidx_t chance, saidx_t incval) {
  budget->chance = chance;
  budget->remain = budget->incval = incval;
}

template <typename saidx_t>
inline int32_t trbudget_check(trbudget_t<saidx_t> *budget, saidx_t size) {
  if(size <= budget->remain) { budget->remain -= size; return 1; }
  if(budget->chance == 0) { budget->count += size; return 0; }
  budget->remain += budget->incval - size;
  budget->chance -= 1;
  return 1;
}

template <typename saidx_t>
inline void tr_partition(const saidx_t *ISAd, saidx_t *first, saidx_t *middle, saidx_t *last,
                         saidx_t **pa, saidx_t **pb, saidx_t v) {
  saidx_t *a, *b, *c, *d, *e, *f;
  saidx_t t, s;
  saidx_t x = 0;

  for(b = middle - 1; (++b < last) && ((x = ISAd[*b]) == v);) { }
  if(((a = b) < last) && (x < v)) {
    for(; (++b < last) && ((x = ISAd[*b]) <= v);) {
      if(x == v) { std::swap(*b, *a); ++a; }
    }
  }
  for(c = last; (b < --c) && ((x = ISAd[*c]) == v);) { }
  if((b < (d = c)) && (x > v)) {
    for(; (b < --c) && ((x = ISAd[*c]) >= v);) {
      if(x == v) { std::swap(*c, *d); --d; }
    }
  }
  for(; b < c;) {
    std::swap(*b, *c);
    for(; (++b < c) && ((x = ISAd[*b]) <= v);) {
      if(x == v) { std::swap(*b, *a); ++a; }
    }
    for(; (b < --c) && ((x = ISAd[*c]) >= v);) {
      if(x == v) { std::swap(*c, *d); --d; }
    }
  }

  if(a <= d) {
    c = b - 1;
    if((s = a - first) > (t = b - a)) { s = t; }
    for(e = first, f = b - s; 0 < s; --s, ++e, ++f) { std::swap(*e, *f); }
    if((s = d - c) > (t = last - d - 1)) { s = t; }
    for(e = b, f = last - s; 0 < s; --s, ++e, ++f) { std::swap(*e, *f); }
    first += (b - a), last -= (d - c);
  }
  *pa = first, *pb = last;
}

template <typename saidx_t>
inline void tr_copy(saidx_t *ISA, const saidx_t *SA, saidx_t *first, saidx_t *a, saidx_t *b, saidx_t *last,
                    saidx_t depth) {
  /* sort suffixes of middle partition
     by using sorted order of suffixes of left and right partition. */
  saidx_t *c, *d, *e;
  saidx_t s, v;

  v = b - SA - 1;
  for(c = first, d = a - 1; c <= d; ++c) {
    if((0 <= (s = *c - depth)) && (ISA[s] == v)) {
      *++d = s;
      ISA[s] = d - SA;
    }
  }
  for(c = last - 1, e = d + 1, d = b; e < d; --c) {
    if((0 <= (s = *c - depth)) && (ISA[s] == v)) {
      *--d = s;
      ISA[s] = d - SA;
    }
  }
}

template <typename saidx_t>
inline void tr_partialcopy(saidx_t *ISA, const saidx_t *SA, saidx_t *first, saidx_t *a, saidx_t *b, saidx_t *last,
                           saidx_t depth) {
  saidx_t *c, *d, *e;
  saidx_t s, v;
  saidx_t rank, lastrank, newrank = -1;

  v = b - SA - 1;
  lastrank = -1;
  for(c = first, d = a - 1; c <= d; ++c) {
    if((0 <= (s = *c - depth)) && (ISA[s] == v)) {
      *++d = s;
      rank = ISA[s + depth];
      if(lastrank != rank) { lastrank = rank; newrank = d - SA; }
      ISA[s] = newrank;
    }
  }

  lastrank = -1;
  for(e = d; first <= e; --e) {
    rank = ISA[*e];
    if(lastrank != rank) { lastrank = rank; newrank = e - SA; }
    if(newrank != rank) { ISA[*e] = newrank; }
  }

  lastrank = -1;
  for(c = last - 1, e = d + 1, d = b; e < d; --c) {
    if((0 <= (s = *c - depth)) && (ISA[s] == v)) {
      *--d = s;
      rank = ISA[s + depth];
      if(lastrank != rank) { lastrank = rank; newrank = d - SA; }
      ISA[s] = newrank;
    }
  }
}

template <typename saidx_t>
inline void tr_introsort(saidx_t *ISA, const saidx_t *ISAd,
                         saidx_t *SA, saidx_t *first, saidx_t *last, trbudget_t<saidx_t> *budget) {
  struct { const saidx_t *a; saidx_t *b, *c; int32_t d, e; }stack[libdivsufsort_config<saidx_t>::TR_STACKSIZE];
  saidx_t *a, *b, *c;
  saidx_t v, x = 0;
  saidx_t incr = ISAd - ISA;
  int32_t limit, next;
  int32_t ssize, trlink = -1;

  for(ssize = 0, limit = tr_ilg((saidx_t)(last - first));;) {

    if(limit < 0) {
      if(limit == -1) {
        /* tandem repeat partition */
        tr_partition(ISAd - incr, first, first, last, &a, &b, (saidx_t)(last - SA - 1));

        /* update ranks */
        if(a < last) {
          for(c = first, v = a - SA - 1; c < a; ++c) { ISA[*c] = v; }
        }
        if(b < last) {
          for(c = a, v = b - SA - 1; c < b; ++c) { ISA[*c] = v; }
        }

        /* push */
        if(1 < (b - a)) {
          STACK_PUSH5(NULL, a, b, 0, 0);
          STACK_PUSH5(ISAd - incr, first, last, -2, trlink);
          trlink = ssize - 2;
        }
        if((a - first) <= (last - b)) {
          if(1 < (a - first)) {
            STACK_PUSH5(ISAd, b, last, tr_ilg((saidx_t)(last - b)), trlink);
            last = a, limit = tr_ilg((saidx_t)(a - first));
          } else if(1 < (last - b)) {
            first = b, limit = tr_ilg((saidx_t)(last - b));
          } else {
            STACK_POP5(ISAd, first, last, limit, trlink);
          }
        } else {
          if(1 < (last - b)) {
            STACK_PUSH5(ISAd, first, a, tr_ilg((saidx_t)(a - first)), trlink);
            first = b, limit = tr_ilg((saidx_t)(last - b));
          } else if(1 < (a - first)) {
            last = a, limit = tr_ilg((saidx_t)(a - first));
          } else {
            STACK_POP5(ISAd, first, last, limit, trlink);
          }
        }
      } else if(limit == -2) {
        /* tandem repeat copy */
        a = stack[--ssize].b, b = stack[ssize].c;
        if(stack[ssize].d == 0) {
          tr_copy(ISA, SA, first, a, b, last, (saidx_t)(ISAd - ISA));
        } else {
          if(0 <= trlink) { stack[trlink].d = -1; }
          tr_partialcopy(ISA, SA, first, a, b, last, (saidx_t)(ISAd - ISA));
        }
        STACK_POP5(ISAd, first, last, limit, trlink);
      } else {
        /* sorted partition */
        if(0 <= *first) {
          a = first;
          do { ISA[*a] = a - SA; } while((++a < last) && (0 <= *a));
          first = a;
        }
        if(first < last) {
          a = first; do { *a = ~*a; } while(*++a < 0);
          next = (ISA[*a] != ISAd[*a]) ? tr_ilg((saidx_t)(a - first + 1)) : -1;
          if(++a < last) { for(b = first, v = a - SA - 1; b < a; ++b) { ISA[*b] = v; } }

          /* push */
          if(trbudget_check(budget, (saidx_t)(a - first))) {
            if((a - first) <= (last - a)) {
              STACK_PUSH5(ISAd, a, last, -3, trlink);
              ISAd += incr, last = a, limit = next;
            } else {
              if(1 < (last - a)) {
                STACK_PUSH5(ISAd + incr, first, a, next, trlink);
                first = a, limit = -3;
              } else {
                ISAd += incr, last = a, limit = next;
              }
            }
          } else {
            if(0 <= trlink) { stack[trlink].d = -1; }
            if(1 < (last - a)) {
              first = a, limit = -3;
            } else {
              STACK_POP5(ISAd, first, last, limit, trlink);
            }
          }
        } else {
          STACK_POP5(ISAd, first, last, limit, trlink);
        }
      }
      continue;
    }

    if((last - first) <= TR_INSERTIONSORT_THRESHOLD) {
      tr_insertionsort(ISAd, first, last);
      limit = -3;
      continue;
    }

    if(limit-- == 0) {
      tr_heapsort(ISAd, first, (saidx_t)(last - first));
      for(a = last - 1; first < a; a = b) {
        for(x = ISAd[*a], b = a - 1; (first <= b) && (ISAd[*b] == x); --b) { *b = ~*b; }
      }
      limit = -3;
      continue;
    }

    /* choose pivot */
    a = tr_pivot(ISAd, first, last);
    std::swap(*first, *a);
    v = ISAd[*first];

    /* partition */
    tr_partition(ISAd, first, first + 1, last, &a, &b, v);
    if((last - first) != (b - a)) {
      next = (ISA[*a] != v) ? tr_ilg((saidx_t)(b - a)) : -1;

      /* update ranks */
      for(c = first, v = a - SA - 1; c < a; ++c) { ISA[*c] = v; }
      if(b < last) { for(c = a, v = b - SA - 1; c < b; ++c) { ISA[*c] = v; } }

      /* push */
      if((1 < (b - a)) && (trbudget_check(budget, (saidx_t)(b - a)))) {
        if((a - first) <= (last - b)) {
          if((last - b) <= (b - a)) {
            if(1 < (a - first)) {
              STACK_PUSH5(ISAd + incr, a, b, next, trlink);
              STACK_PUSH5(ISAd, b, last, limit, trlink);
              last = a;
            } else if(1 < (last - b)) {
              STACK_PUSH5(ISAd + incr, a, b, next, trlink);
              first = b;
            } else {
              ISAd += incr, first = a, last = b, limit = next;
            }
          } else if((a - first) <= (b - a)) {
            if(1 < (a - first)) {
              STACK_PUSH5(ISAd, b, last, limit, trlink);
              STACK_PUSH5(ISAd + incr, a, b, next, trlink);
              last = a;
            } else {
              STACK_PUSH5(ISAd, b, last, limit, trlink);
              ISAd += incr, first = a, last = b, limit = next;
            }
          } else {
            STACK_PUSH5(ISAd, b, last, limit, trlink);
            STACK_PUSH5(ISAd, first, a, limit, trlink);
            ISAd += incr, first = a, last = b, limit = next;
          }
        } else {
          if((a - first) <= (b - a)) {
            if(1 < (last - b)) {
              STACK_PUSH5(ISAd + incr, a, b, next, trlink);
              STACK_PUSH5(ISAd, first, a, limit, trlink);
              first = b;
            } else if(1 < (a - first)) {
              STACK_PUSH5(ISAd + incr, a, b, next, trlink);
              last = a;
            } else {
              ISAd += incr, first = a, last = b, limit = next;
            }
          } else if((last - b) <= (b - a)) {
            if(1 < (last - b)) {
              STACK_PUSH5(ISAd, first, a, limit, trlink);
              STACK_PUSH5(ISAd + incr, a, b, next, trlink);
              first = b;
            } else {
              STACK_PUSH5(ISAd, first, a, limit, trlink);
              ISAd += incr, first = a, last = b, limit = next;
            }
          } else {
            STACK_PUSH5(ISAd, first, a, limit, trlink);
            STACK_PUSH5(ISAd, b, last, limit, trlink);
            ISAd += incr, first = a, last = b, limit = next;
          }
        }
      } else {
        if((1 < (b - a)) && (0 <= trlink)) { stack[trlink].d = -1; }
        if((a - first) <= (last - b)) {
          if(1 < (a - first)) {
            STACK_PUSH5(ISAd, b, last, limit, trlink);
            last = a;
          } else if(1 < (last - b)) {
            first = b;
          } else {
            STACK_POP5(ISAd, first, last, limit, trlink);
          }
        } else {
          if(1 < (last - b)) {
            STACK_PUSH5(ISAd, first, a, limit, trlink);
            first = b;
          } else if(1 < (a - first)) {
            last = a;
          } else {
            STACK_POP5(ISAd, first, last, limit, trlink);
          }
        }
      }
    } else {
      if(trbudget_check(budget, (saidx_t)(last - first))) {
        limit = tr_ilg((saidx_t)(last - first)), ISAd += incr;
      } else {
        if(0 <= trlink) { stack[trlink].d = -1; }
        STACK_POP5(ISAd, first, last, limit, trlink);
      }
    }
  }
}

/*- Function -*/

/* Tandem repeat sort */
template <typename saidx_t>
inline void trsort(saidx_t *ISA, saidx_t *SA, saidx_t n, saidx_t depth) {
  saidx_t *ISAd;
  saidx_t *first, *last;
  trbudget_t<saidx_t> budget;
  saidx_t t, skip, unsorted;

  trbudget_init(&budget, (saidx_t)(tr_ilg(n) * 2 / 3), n);
/*  trbudget_init(&budget, tr_ilg(n) * 3 / 4, n); */
  for(ISAd = ISA + depth; -n < *SA; ISAd += ISAd - ISA) {
    first = SA;
    skip = 0;
    unsorted = 0;
    do {
      if((t = *first) < 0) { first -= t; skip += t; }
      else {
        if(skip != 0) { *(first + skip) = skip; skip = 0; }
        last = SA + ISA[t] + 1;
        if(1 < (last - first)) {
          budget.count = 0;
          tr_introsort(ISA, ISAd, SA, first, last, &budget);
          if(budget.count != 0) { unsorted += budget.count; }
          else { skip = first - last; }
        } else if((last - first) == 1) {
          skip = -1;
        }
        first = last;
      }
    } while(first < (SA + n));
    if(skip != 0) { *(first + skip) = skip; }
    if(unsorted == 0) { break; }
  }
}

/* Sorts suffixes of type B*. */
template <typename saidx_t>
inline saidx_t sort_typeBstar(const uint8_t *T, saidx_t *SA, saidx_t *bucket_A, saidx_t *bucket_B, saidx_t n) {
  saidx_t *PAb, *ISAb, *buf;
#ifdef _OPENMP
  saidx_t *curbuf;
  saidx_t l;
#endif
  saidx_t i, j, k, t, m, bufsize;
  int32_t c0, c1;
#ifdef _OPENMP
  int32_t d0, d1;
  int tmp;
#endif

  /* Initialize bucket arrays. */
  for(i = 0; i < BUCKET_A_SIZE; ++i) { bucket_A[i] = 0; }
  for(i = 0; i < BUCKET_B_SIZE; ++i) { bucket_B[i] = 0; }

  /* Count the number of occurrences of the first one or two characters of each
     type A, B and B* suffix. Moreover, store the beginning position of all
     type B* suffixes into the array SA. */
  for(i = n - 1, m = n, c0 = T[n - 1]; 0 <= i;) {
    /* type A suffix. */
    do { ++BUCKET_A(c1 = c0); } while((0 <= --i) && ((c0 = T[i]) >= c1));
    if(0 <= i) {
      /* type B* suffix. */
      ++BUCKET_BSTAR(c0, c1);
      SA[--m] = i;
      /* type B suffix. */
      for(--i, c1 = c0; (0 <= i) && ((c0 = T[i]) <= c1); --i, c1 = c0) {
        ++BUCKET_B(c0, c1);
      }
    }
  }
  m = n - m;
/*
note:
  A type B* suffix is lexicographically smaller than a type B suffix that
  begins with the same first two characters.
*/

  /* Calculate the index of start/end point of each bucket. */
  for(c0 = 0, i = 0, j = 0; c0 < ALPHABET_SIZE; ++c0) {
    t = i + BUCKET_A(c0);
    BUCKET_A(c0) = i + j; /* start point */
    i = t + BUCKET_B(c0, c0);
    for(c1 = c0 + 1; c1 < ALPHABET_SIZE; ++c1) {
      j += BUCKET_BSTAR(c0, c1);
      BUCKET_BSTAR(c0, c1) = j; /* end point */
      i += BUCKET_B(c0, c1);
    }
  }

  if(0 < m) {
    /* Sort the type B* suffixes by their first two characters. */
    PAb = SA + n - m; ISAb = SA + m;
    for(i = m - 2; 0 <= i; --i) {
      t = PAb[i], c0 = T[t], c1 = T[t + 1];
      SA[--BUCKET_BSTAR(c0, c1)] = i;
    }
    t = PAb[m - 1], c0 = T[t], c1 = T[t + 1];
    SA[--BUCKET_BSTAR(c0, c1)] = m - 1;

    /* Sort the type B* substrings using sssort. */
#ifdef _OPENMP
    tmp = omp_get_max_threads();
    buf = SA + m, bufsize = (n - (2 * m)) / tmp;
    c0 = ALPHABET_SIZE - 2, c1 = ALPHABET_SIZE - 1, j = m;
#pragma omp parallel default(shared) private(curbuf, k, l, d0, d1, tmp)
    {
      tmp = omp_get_thread_num();
      curbuf = buf + tmp * bufsize;
      k = 0;
      for(;;) {
        #pragma omp critical(sssort_lock)
        {
          if(0 < (l = j)) {
            d0 = c0, d1 = c1;
            do {
              k = BUCKET_BSTAR(d0, d1);
              if(--d1 <= d0) {
                d1 = ALPHABET_SIZE - 1;
                if(--d0 < 0) { break; }
              }
            } while(((l - k) <= 1) && (0 < (l = k)));
            c0 = d0, c1 = d1, j = k;
          }
        }
        if(l == 0) { break; }
        sssort(T, PAb, SA + k, SA + l,
               curbuf, bufsize, (saidx_t)2, n, *(SA + k) == (m - 1));
      }
    }
#else
    buf = SA + m, bufsize = n - (2 * m);
    for(c0 = ALPHABET_SIZE - 2, j = m; 0 < j; --c0) {
      for(c1 = ALPHABET_SIZE - 1; c0 < c1; j = i, --c1) {
        i = BUCKET_BSTAR(c0, c1);
        if(1 < (j - i)) {
          sssort(T, PAb, SA + i, SA + j,
                 buf, bufsize, (saidx_t)2, n, *(SA + i) == (m - 1));
        }
      }
    }
#endif

    /* Compute ranks of type B* substrings. */
    for(i = m - 1; 0 <= i; --i) {
      if(0 <= SA[i]) {
        j = i;
        do { ISAb[SA[i]] = i; } while((0 <= --i) && (0 <= SA[i]));
        SA[i + 1] = i - j;
        if(i <= 0) { break; }
      }
      j = i;
      do { ISAb[SA[i] = ~SA[i]] = j; } while(SA[--i] < 0);
      ISAb[SA[i]] = j;
    }

    /* Construct the inverse suffix array of type B* suffixes using trsort. */
    trsort(ISAb, SA, m, (saidx_t)1);

    /* Set the sorted order of tyoe B* suffixes. */
    for(i = n - 1, j = m, c0 = T[n - 1]; 0 <= i;) {
      for(--i, c1 = c0; (0 <= i) && ((c0 = T[i]) >= c1); --i, c1 = c0) { }
      if(0 <= i) {
        t = i;
        for(--i, c1 = c0; (0 <= i) && ((c0 = T[i]) <= c1); --i, c1 = c0) { }
        SA[ISAb[--j]] = ((t == 0) || (1 < (t - i))) ? t : ~t;
      }
    }

    /* Calculate the index of start/end point of each bucket. */
    BUCKET_B(ALPHABET_SIZE - 1, ALPHABET_SIZE - 1) = n; /* end point */
    for(c0 = ALPHABET_SIZE - 2, k = m - 1; 0 <= c0; --c0) {
      i = BUCKET_A(c0 + 1) - 1;
      for(c1 = ALPHABET_SIZE - 1; c0 < c1; --c1) {
        t = i - BUCKET_B(c0, c1);
        BUCKET_B(c0, c1) = i; /* end point */

        /* Move all type B* suffixes to the correct position. */
        for(i = t, j = BUCKET_BSTAR(c0, c1);
            j <= k;
            --i, --k) { SA[i] = SA[k]; }
      }
      BUCKET_BSTAR(c0, c0 + 1) = i - BUCKET_B(c0, c0) + 1; /* start point */
      BUCKET_B(c0, c0) = i; /* end point */
    }
  }

  return m;
}

/* Constructs the suffix array by using the sorted order of type B* suffixes. */
template <typename saidx_t>
inline void construct_SA(const uint8_t *T, saidx_t *SA, saidx_t *bucket_A, saidx_t *bucket_B, saidx_t n, saidx_t m) {
  saidx_t *i, *j, *k;
  saidx_t s;
  int32_t c0, c1, c2;

  if(0 < m) {
    /* Construct the sorted order of type B suffixes by using
       the sorted order of type B* suffixes. */
    for(c1 = ALPHABET_SIZE - 2; 0 <= c1; --c1) {
      /* Scan the suffix array from right to left. */
      for(i = SA + BUCKET_BSTAR(c1, c1 + 1),
          j = SA + BUCKET_A(c1 + 1) - 1, k = NULL, c2 = -1;
          i <= j;
          --j) {
        if(0 < (s = *j)) {
          assert(T[s] == c1);
          assert(((s + 1) < n) && (T[s] <= T[s + 1]));
          assert(T[s - 1] <= T[s]);
          *j = ~s;
          c0 = T[--s];
          if((0 < s) && (T[s - 1] > c0)) { s = ~s; }
          if(c0 != c2) {
            if(0 <= c2) { BUCKET_B(c2, c1) = k - SA; }
            k = SA + BUCKET_B(c2 = c0, c1);
          }
          assert(k < j);
          *k-- = s;
        } else {
          assert(((s == 0) && (T[s] == c1)) || (s < 0));
          *j = ~s;
        }
      }
    }
  }

  /* Construct the suffix array by using
     the sorted order of type B suffixes. */
  k = SA + BUCKET_A(c2 = T[n - 1]);
  *k++ = (T[n - 2] < c2) ? ~(n - 1) : (n - 1);
  /* Scan the suffix array from left to right. */
  for(i = SA, j = SA + n; i < j; ++i) {
    if(0 < (s = *i)) {
      assert(T[s - 1] >= T[s]);
      c0 = T[--s];
      if((s == 0) || (T[s - 1] < c0)) { s = ~s; }
      if(c0 != c2) {
        BUCKET_A(c2) = k - SA;
        k = SA + BUCKET_A(c2 = c0);
      }
      assert(i < k);
      *k++ = s;
    } else {
      assert(s < 0);
      *i = ~s;
    }
  }
}

/* Constructs the burrows-wheeler transformed string directly
   by using the sorted order of type B* suffixes. */
template <typename saidx_t>
inline saidx_t construct_BWT(const uint8_t *T, saidx_t *SA, saidx_t *bucket_A, saidx_t *bucket_B, saidx_t n, saidx_t m) {
  saidx_t *i, *j, *k, *orig;
  saidx_t s;
  int32_t c0, c1, c2;

  if(0 < m) {
    /* Construct the sorted order of type B suffixes by using
       the sorted order of type B* suffixes. */
    for(c1 = ALPHABET_SIZE - 2; 0 <= c1; --c1) {
      /* Scan the suffix array from right to left. */
      for(i = SA + BUCKET_BSTAR(c1, c1 + 1),
          j = SA + BUCKET_A(c1 + 1) - 1, k = NULL, c2 = -1;
          i <= j;
          --j) {
        if(0 < (s = *j)) {
          assert(T[s] == c1);
          assert(((s + 1) < n) && (T[s] <= T[s + 1]));
          assert(T[s - 1] <= T[s]);
          c0 = T[--s];
          *j = ~((saidx_t)c0);
          if((0 < s) && (T[s - 1] > c0)) { s = ~s; }
          if(c0 != c2) {
            if(0 <= c2) { BUCKET_B(c2, c1) = k - SA; }
            k = SA + BUCKET_B(c2 = c0, c1);
          }
          assert(k < j);
          *k-- = s;
        } else if(s != 0) {
          *j = ~s;
#ifndef NDEBUG
        } else {
          assert(T[s] == c1);
#endif
        }
      }
    }
  }

  /* Construct the BWTed string by using
     the sorted order of type B suffixes. */
  k = SA + BUCKET_A(c2 = T[n - 1]);
  *k++ = (T[n - 2] < c2) ? ~((saidx_t)T[n - 2]) : (n - 1);
  /* Scan the suffix array from left to right. */
  for(i = SA, j = SA + n, orig = SA; i < j; ++i) {
    if(0 < (s = *i)) {
      assert(T[s - 1] >= T[s]);
      c0 = T[--s];
      *i = c0;
      if((0 < s) && (T[s - 1] < c0)) { s = ~((saidx_t)T[s - 1]); }
      if(c0 != c2) {
        BUCKET_A(c2) = k - SA;
        k = SA + BUCKET_A(c2 = c0);
      }
      assert(i < k);
      *k++ = s;
    } else if(s != 0) {
      *i = ~s;
    } else {
      orig = i;
    }
  }

  return orig - SA;
}

/*- Function -*/

template <typename saidx_t>
int32_t
divsufsort(const uint8_t *T, saidx_t *SA, saidx_t n) {
  saidx_t *bucket_A, *bucket_B;
  saidx_t m;
  int32_t err = 0;

  /* Check arguments. */
  if((T == NULL) || (SA == NULL) || (n < 0)) { return -1; }
  else if(n == 0) { return 0; }
  else if(n == 1) { SA[0] = 0; return 0; }
  else if(n == 2) { m = (T[0] < T[1]); SA[m ^ 1] = 0, SA[m] = 1; return 0; }

  bucket_A = (saidx_t *)malloc(BUCKET_A_SIZE * sizeof(saidx_t));
  bucket_B = (saidx_t *)malloc(BUCKET_B_SIZE * sizeof(saidx_t));

  /* Suffixsort. */
  if((bucket_A != NULL) && (bucket_B != NULL)) {
    m = sort_typeBstar(T, SA, bucket_A, bucket_B, n);
    construct_SA(T, SA, bucket_A, bucket_B, n, m);
  } else {
    err = -2;
  }

  free(bucket_B);
  free(bucket_A);

  return err;
}

// template <typename saidx_t>
// saidx_t
// divbwt(const uint8_t *T, uint8_t *U, saidx_t *A, saidx_t n) {
//   saidx_t *B;
//   saidx_t *bucket_A, *bucket_B;
//   saidx_t m, pidx, i;
//
//   /* Check arguments. */
//   if((T == NULL) || (U == NULL) || (n < 0)) { return -1; }
//   else if(n <= 1) { if(n == 1) { U[0] = T[0]; } return n; }
//
//   if((B = A) == NULL) { B = (saidx_t *)malloc((size_t)(n + 1) * sizeof(saidx_t)); }
//   bucket_A = (saidx_t *)malloc(BUCKET_A_SIZE * sizeof(saidx_t));
//   bucket_B = (saidx_t *)malloc(BUCKET_B_SIZE * sizeof(saidx_t));
//
//   /* Burrows-Wheeler Transform. */
//   if((B != NULL) && (bucket_A != NULL) && (bucket_B != NULL)) {
//     m = sort_typeBstar(T, B, bucket_A, bucket_B, n);
//     pidx = construct_BWT(T, B, bucket_A, bucket_B, n, m);
//
//     /* Copy to output string. */
//     U[0] = T[n - 1];
//     for(i = 0; i < pidx; ++i) { U[i + 1] = (uint8_t)B[i]; }
//     for(i += 1; i < n; ++i) { U[i] = (uint8_t)B[i]; }
//     pidx += 1;
//   } else {
//     pidx = -2;
//   }
//
//   free(bucket_B);
//   free(bucket_A);
//   if(A == NULL) { free(B); }
//
//   return pidx;
// }

inline int32_t divsufsort64(const uint8_t *T, int64_t *SA, int64_t n) {
    return divsufsort(T, SA, n);
}

template <typename saidx_t>
inline int _compare(const uint8_t *T, saidx_t Tsize, const uint8_t *P, saidx_t Psize, saidx_t suf, saidx_t *match) {
  saidx_t i, j;
  int32_t r;
  for(i = suf + *match, j = *match, r = 0;
      (i < Tsize) && (j < Psize) && ((r = T[i] - P[j]) == 0); ++i, ++j) { }
  *match = j;
  return (r == 0) ? -(j != Psize) : r;
}

/* Burrows-Wheeler transform. */
// TODO: use?
// template <typename saidx_t>
// int32_t
// bw_transform(const uint8_t *T, uint8_t *U, saidx_t *SA,
//              saidx_t n, saidx_t *idx) {
//   saidx_t *A, i, j, p, t;
//   int32_t c;
//
//   /* Check arguments. */
//   if((T == NULL) || (U == NULL) || (n < 0) || (idx == NULL)) { return -1; }
//   if(n <= 1) {
//     if(n == 1) { U[0] = T[0]; }
//     *idx = n;
//     return 0;
//   }
//
//   if((A = SA) == NULL) {
//     i = divbwt(T, U, NULL, n);
//     if(0 <= i) { *idx = i; i = 0; }
//     return (int32_t)i;
//   }
//
//   /* BW transform. */
//   if(T == U) {
//     t = n;
//     for(i = 0, j = 0; i < n; ++i) {
//       p = t - 1;
//       t = A[i];
//       if(0 <= p) {
//         c = T[j];
//         U[j] = (j <= p) ? T[p] : (uint8_t)A[p];
//         A[j] = c;
//         j++;
//       } else {
//         *idx = i;
//       }
//     }
//     p = t - 1;
//     if(0 <= p) {
//       c = T[j];
//       U[j] = (j <= p) ? T[p] : (uint8_t)A[p];
//       A[j] = c;
//     } else {
//       *idx = i;
//     }
//   } else {
//     U[0] = T[n - 1];
//     for(i = 0; A[i] != 0; ++i) { U[i + 1] = T[A[i] - 1]; }
//     *idx = i + 1;
//     for(++i; i < n; ++i) { U[i] = T[A[i] - 1]; }
//   }
//
//   if(SA == NULL) {
//     /* Deallocate memory. */
//     free(A);
//   }
//
//   return 0;
// }

// TODO: use?
/* Inverse Burrows-Wheeler transform. */
// template <typename saidx_t>
// int32_t
// inverse_bw_transform(const uint8_t *T, uint8_t *U, saidx_t *A,
//                      saidx_t n, saidx_t idx) {
//   saidx_t C[ALPHABET_SIZE];
//   uint8_t D[ALPHABET_SIZE];
//   saidx_t *B;
//   saidx_t i, p;
//   int32_t c, d;
//
//   /* Check arguments. */
//   if((T == NULL) || (U == NULL) || (n < 0) || (idx < 0) ||
//      (n < idx) || ((0 < n) && (idx == 0))) {
//     return -1;
//   }
//   if(n <= 1) { return 0; }
//
//   if((B = A) == NULL) {
//     /* Allocate n*sizeof(saidx_t) bytes of memory. */
//     if((B = (saidx_t *)malloc((size_t)n * sizeof(saidx_t))) == NULL) { return -2; }
//   }
//
//   /* Inverse BW transform. */
//   for(c = 0; c < ALPHABET_SIZE; ++c) { C[c] = 0; }
//   for(i = 0; i < n; ++i) { ++C[T[i]]; }
//   for(c = 0, d = 0, i = 0; c < ALPHABET_SIZE; ++c) {
//     p = C[c];
//     if(0 < p) {
//       C[c] = i;
//       D[d++] = (uint8_t)c;
//       i += p;
//     }
//   }
//   for(i = 0; i < idx; ++i) { B[C[T[i]]++] = i; }
//   for( ; i < n; ++i)       { B[C[T[i]]++] = i + 1; }
//   for(c = 0; c < d; ++c) { C[c] = C[D[c]]; }
//   for(i = 0, p = idx; i < n; ++i) {
//     U[i] = D[binarysearch_lower(C, d, p)];
//     p = B[p - 1];
//   }
//
//   if(A == NULL) {
//     /* Deallocate memory. */
//     free(B);
//   }
//
//   return 0;
// }

}

#endif
