[HDU 1358]Period[kmp求周期]

题意:

每一个power前缀的周期数(>1).

思路:

kmp的next. 每一个前缀都询问一遍.

#include <cstring>#include <cstdio>const int MAXN = 1000005;int next[MAXN];char s[MAXN];//93MS5092Kvoid prekmp(){    next[0] = -1;    int j = -1;    for(int i=1;s[i];i++)    {        while(j!=-1 && s[j+1]!=s[i])    j = next[j];        if(s[j+1]==s[i])    j++;        next[i] = j;    }}int main(){    int n,cas = 0;    while(scanf("%d",&n) && n)    {        scanf("%s",s);        printf("Test case #%d\n",++cas);        prekmp();        int len;        for(int i=1;i<n;i++)        {            len = i-next[i];            int k;            if(!((i+1)%len))            {                if((k=(i+1)/len)>1)                    printf("%d %d\n",i+1,k);            }        }        printf("\n");    }}