SH-Quizzes/ACMOJ-2045.cpp

#include <algorithm>
#include <cstdio>
#include <cstring>
using namespace std;
typedef long long LL;
const int L_TYPE = 0;
const int S_TYPE = 1;
const int maxn = 1e6 + 10;
int n;
char s[maxn];
namespace __SA_IS {
int a[2000100], sa[2000100], typ[2000100], c[1000100], p[2000100],
    sbuc[1000100], lbuc[1000100], name[1000100];

inline int islms(int *typ, int i) { return !typ[i] && (i == 1 || typ[i - 1]); }

int cmp(int *s, int *typ, int p, int q) {
  do {
    if (s[p] != s[q]) return 1;
    p++;
    q++;
  } while (!islms(typ, p) && !islms(typ, q));
  return (!islms(typ, p) || !islms(typ, q) || s[p] != s[q]);
}

void isort(int *s, int *sa, int *typ, int *c, int n, int m) {
  int i;
  for (lbuc[0] = sbuc[0] = c[0], i = 1; i <= m; i++) {
    lbuc[i] = c[i - 1] + 1;
    sbuc[i] = c[i];
  }
  for (i = 1; i <= n; i++)
    if (sa[i] > 1 && typ[sa[i] - 1]) sa[lbuc[s[sa[i] - 1]]++] = sa[i] - 1;
  for (i = n; i >= 1; i--)
    if (sa[i] > 1 && !typ[sa[i] - 1]) sa[sbuc[s[sa[i] - 1]]--] = sa[i] - 1;
}

void build_sa(int *s, int *sa, int *typ, int *c, int *p, int n, int m) {
  int i;
  for (i = 0; i <= m; i++) c[i] = 0;
  for (i = 1; i <= n; i++) c[s[i]]++;
  for (i = 1; i <= m; i++) c[i] += c[i - 1];
  typ[n] = 0;
  for (i = n - 1; i >= 1; i--)
    if (s[i] < s[i + 1])
      typ[i] = 0;
    else if (s[i] > s[i + 1])
      typ[i] = 1;
    else
      typ[i] = typ[i + 1];
  int cnt = 0;
  for (i = 1; i <= n; i++)
    if (!typ[i] && (i == 1 || typ[i - 1])) p[++cnt] = i;
  for (i = 1; i <= n; i++) sa[i] = 0;
  for (i = 0; i <= m; i++) sbuc[i] = c[i];
  for (i = 1; i <= cnt; i++) sa[sbuc[s[p[i]]]--] = p[i];
  isort(s, sa, typ, c, n, m);
  int last = 0, t = -1, x;
  for (i = 1; i <= n; i++) {
    x = sa[i];
    if (!typ[x] && (x == 1 || typ[x - 1])) {
      if (!last || cmp(s, typ, x, last))
        name[x] = ++t;
      else
        name[x] = t;
      last = x;
    }
  }
  for (i = 1; i <= cnt; i++) s[n + i] = name[p[i]];
  if (t < cnt - 1)
    build_sa(s + n, sa + n, typ + n, c + m + 1, p + n, cnt, t);
  else
    for (i = 1; i <= cnt; i++) sa[n + s[n + i] + 1] = i;
  for (i = 0; i <= m; i++) sbuc[i] = c[i];
  for (i = 1; i <= n; i++) sa[i] = 0;
  for (i = cnt; i >= 1; i--) sa[sbuc[s[p[sa[n + i]]]]--] = p[sa[n + i]];
  isort(s, sa, typ, c, n, m);
}
}  // namespace __SA_IS
void SA_IS(char *s, int n, int *sa, int *rk) {
  using namespace __SA_IS;
  for (int i = 1; i <= n; i++) a[i] = s[i];
  a[++n] = 0;
  build_sa(a, sa, typ, c, p, n, 256);
  n--;
  for (int i = 1; i <= n; i++) sa[i] = sa[i + 1];
  for (int i = 1; i <= n; i++) rk[sa[i]] = i;
}
void computeHeight(char *s, int n, int *sa, int *rk, int *height) {
  int k = 0;
  for (int i = 1; i <= n; i++) {
    if (rk[i] == 1) {
      height[rk[i]] = 0;
      continue;
    }
    if (k > 0) {
      k--;
    }
    int j = sa[rk[i] - 1];
    while (i + k <= n && j + k <= n && s[i + k] == s[j + k]) {
      k++;
    }
    height[rk[i]] = k;
  }
}
LL GetPairMin(int *height, int n) {
  int *index_stack = 1 + new int[n + 10]();
  index_stack[-1] = 0;
  int s_cnt = 0;
  LL res = 0, cur = 0;
  index_stack[s_cnt++] = 1;
  for (int i = 2; i <= n; i++) {
    while (s_cnt > 0 && height[index_stack[s_cnt - 1]] >= height[i]) {
      s_cnt--;
      cur -= (index_stack[s_cnt] - index_stack[s_cnt - 1]) *
             (LL)height[index_stack[s_cnt]];
    }
    index_stack[s_cnt++] = i;
    cur += (index_stack[s_cnt - 1] - index_stack[s_cnt - 2]) * (LL)height[i];
    res += cur;
  }
  delete[] (index_stack - 1);
  return res;
}
LL calc(char *s, int n) {
  int *sa = new int[n << 4]();
  int *rk = new int[n << 4]();
  int *height = new int[n << 4]();
  SA_IS(s, n, sa, rk);
  computeHeight(s, n, sa, rk, height);
  LL res = 0;
  for (int i = 1; i <= n; i++) res += n + 1 - sa[i] - height[i];
  delete[] sa;
  delete[] rk;
  delete[] height;
  return res;
}
int main() {
#ifdef local
  freopen("pro.in", "r", stdin);
#endif
  scanf("%d%s", &n, s + 1);
  LL res = calc(s, n);
  printf("%lld\n", res);
  return 0;
}