【KMP思想求循环节】hdu 1358 hust 1010 poj 2406

#include<iostream>
#include<cstdio>
#include<cstring>
#include<cmath>
#include<stack>
#include<queue>
#include<deque>
#include<map>
#include<algorithm>
using namespace std;
typedef long long LL;
//#pragma comment(linker, "/STACK:102400000,102400000")
/*
HDU - 3746
给出一个字符串，问还需要在后面添加多少个字符才能使它变成由一个前缀循环多次而成
无非求一个next

*/
const double PI = acos(-1.0);
const double eps = 1e-6;
const int INF=0x3f3f3f3f;
const int mod = 1e9;
const int N = 100010;

char s
;
int nex
;
void getnext(char *p)
{
int len = strlen(p);
int k = -1;
nex[0] = k;
for(int i = 1; i < len; i++)
{
while(k!=-1 && p[i]!=p[k+1])
k = nex[k];
if(p[i]==p[k+1])
k++;
nex[i] = k;
}
}
int main()
{
int T;
scanf("%d",&T);
while(T--)
{
scanf("%s",s);
getnext(s);
int len = strlen(s);
int x = nex[len-1]+1;
x = len-x;
if(x == len)
{
printf("%d\n",x);
continue;
}
if(len%x == 0)
puts("0");
else
printf("%d\n",x-len%x);
}
return 0;
}