Hdu_3746 Cyclic Nacklace - 字符串周期规律题目

题目：把串补成最小周期>=2的串需要补的长度

规律：把一个串补成R^k串需要补的长度：补上最小周期 - 长度%最小周期

/************************************************
Author        :DarkTong
Created Time  :2016/8/14 22:26:17
File Name     :Hdu_3746.cpp
*************************************************/

#include <bits/stdc++.h>
using namespace std;
typedef unsigned long long ULL;
typedef long long LL;
const int INF = 0x3f3f3f3f;
const double eps = 1e-9;
const int maxn = 100000 + 10;
char s[maxn];
int nxt[maxn], m;
void getfail(char *P, int *f)
{
//    int m = strlen(P);
    f[0]=0; f[1]=0;
    for(int i=1;i<m;++i)
    {
        int j=f[i];
        while(j&&P[i]!=P[j])j=f[j];
        f[i+1]=P[i]==P[j]?j+1:0;
    }
}

int main()
{
    int T, cas=1;
    scanf("%d", &T);
    while(T--)
    {
        scanf("%s", &s);
        m = strlen(s);
        getfail(s, nxt);
//        for(int i=1;i<=m;++i) cout<<nxt[i]<<" "; cout<<endl;
        int ans = INF;
        ans = m%(m-nxt[m]);
        if(ans==0&&nxt[m]==0) ans=m;
        else if(ans)ans = (m-nxt[m])-ans;
        printf("%d\n", ans);
    }
    
    return 0;
}