后缀数组 POJ 2217 Secretary

#include <cstdio>
#include <cstring>
#include <algorithm>
#include <iostream>
#include <string>

typedef long long ll;
const int N = 1e4 + 5;
std::string t, str;
int sa[N<<1], rank[N<<1];
int height[N<<1];
int tmp[N<<1];

int n, k;
bool cmp_sa(int i, int j) {
if (rank[i] != rank[j]) {
return rank[i] < rank[j];
} else {
int ri = i + k <= n ? rank[i+k] : -1;
int rj = j + k <= n ? rank[j+k] : -1;
return ri < rj;
}
}

void get_sa(std::string S, int *sa) {
n = S.length ();
for (int i=0; i<=n; ++i) {
sa[i] = i;
rank[i] = i < n ? (int) S[i] : -1;
}
for (k=1; k<=n; k<<=1) {
std::sort (sa, sa+n+1, cmp_sa);
tmp[sa[0]] = 0;
for (int i=1; i<=n; ++i) {
tmp[sa[i]] = tmp[sa[i-1]] + (cmp_sa (sa[i-1], sa[i]) ? 1 : 0);
}
for (int i=0; i<=n; ++i) {
rank[i] = tmp[i];
}
}
}

void get_height(std::string S, int *sa, int *height) {
int n = S.length ();
for (int i=0; i<n; ++i) {
rank[sa[i]] = i;
}
int h = 0;
height[0] = 0;
for (int i=0; i<n; ++i) {
int j = sa[rank[i]-1];
if (h > 0) {
h--;
}
for (; j+h<n && i+h<n; h++) {
if (S[j+h] != S[i+h]) {
break;
}
}
height[rank[i]-1] = h;
}
}

int run(int len1, std::string S) {
get_sa (S, sa);
get_height (S, sa, height);
int ret = 0;
for (int i=0; i<S.length (); ++i) {
if ((sa[i]<len1) != (sa[i+1]<len1)) {
ret = std::max (ret, height[i]);
}
}
return ret;
}

int main() {
int T; scanf ("%d", &T);
getchar ();
while (T--) {
getline (std::cin, t);
str = t;
int len1 = t.length ();
getline (std::cin, t);
str += '$' + t;
int ans = run (len1, str);
printf ("Nejdelsi spolecny retezec ma delku %d.\n", ans);
}
return 0;
}