HDU3746 Cyclic Nacklace KMP

http://acm.hdu.edu.cn/showproblem.php?pid=3746

 依然是next数组的操作...找循环节并且补全

#include<cstdio>
#include<cstring>
#include<iostream>
#include<algorithm>
#include<cmath>
#include<queue>
using namespace std;
const int maxn=1000010;
const double eps=1e-8;
const long long modn=1000;
char a[maxn]={};
int nex[maxn]={};
int n;
int doit(){
    int i=0,j=-1;nex[0]=-1;
    while(i<n){
        if(j==-1||a[j]==a[i]){
            nex[++i]=++j;
        }else{
            j=nex[j];
        }
    }
    int z=n-nex[n];
    if(nex[n]==0){
        return n;
    }else if(n%z==0){
        return 0;
    }
    else {
        return z-n%z;
    }
}
int main(){
    int T;
    scanf("%d",&T);
    while(T-->0){
        scanf("%s",&a);
        n=strlen(a);
        printf("%d
",doit());
    }
    return 0;
}