hdu 1358 period

http://acm.hdu.edu.cn/showproblem.php?pid=1358
求某个前缀含几个循环 用kmp的next数组

#include <cstdio>#include <cstring>using namespace std;int Next[1000005];char c[1000005];int main(){    int len;    int cnt=1;    while(scanf("%d",&len)&&len)    {        memset(Next,0,sizeof(Next));        scanf("%s",&c);        printf("Test case #%d\n",cnt);        int i = 0,j=-1;        Next[0]=-1;        while(i<len)        {            if(j==-1||c[i]==c[j])            {                i++;j++;                Next[i]=j;            }            else                j=Next[j];        }        for(int i = 1; i<=len; i++)            if(i%(i-Next[i])==0&&Next[i])                printf("%d %d\n",i,i/(i-Next[i]));        printf("\n");        cnt++;    }}