BZOJ1031 [JSOI2007]字符加密Cipher

把字符串倍长复制了。。。直接后缀数组求出rank就好了QAQ

/**************************************************************
    Problem: 1031
    User: rausen
    Language: C++
    Result: Accepted
    Time:1252 ms
    Memory:4908 kb
****************************************************************/
 
#include <cstdio>
#include <cstring>
#include <algorithm>
  
using namespace std;
const int N = 2e5 + 5;
  
char s[N];
int l, sa[N], rank[N];
int x[N], y[N], sum[N];
  
inline void Sort(int *a, int *b, int *c, int n, int m) {
    static int i;
    for (i = 0; i <= m; ++i) sum[i] = 0;
    for (i = 0; i < n; ++i) ++sum[c[a[i]]];
    for (i = 1; i <= m; ++i) sum[i] += sum[i - 1];
    for (i = n - 1; ~i; --i)
        b[--sum[c[a[i]]]] = a[i];
}
  
void make_sa(char *s) {
    int i, j;
    for (i = 0; i < l; ++i) x[i] = s[i], rank[i] = i;
    Sort(rank, sa, x, l, 256);
    rank[sa[0]] = 1;
    for (i = 1; i < l; ++i)
        rank[sa[i]] = rank[sa[i - 1]] + (x[sa[i]] != x[sa[i - 1]]);
    for (i = 1; i <= l; i <<= 1) {
        for (j = 0; j < l; ++j)
            x[j] = rank[j], y[j] = j + i < l ? rank[j + i] : 0, sa[j] = j;
        Sort(sa, rank, y, l, l), Sort(rank, sa, x, l, l);
        rank[sa[0]] = 1;
        for (j = 1; j < l; ++j)
            rank[sa[j]] = rank[sa[j - 1]] + (x[sa[j]] != x[sa[j - 1]] || y[sa[j]] != y[sa[j - 1]]);
        if (rank[sa[l - 1]] == l) return;
    }
}
  
int main() {
    int i;
    gets(s), l = strlen(s);
    for (i = l; i < l << 1; ++i) s[i] = s[i - l];
    l <<= 1;
    make_sa(s);
    for (i = 0; i < l; ++i)
        if (sa[i] < l / 2) putchar(s[sa[i] + l / 2 - 1]);
    putchar('
');
    return 0;
}