HDU - 3746

https://www.cnblogs.com/chenxiwenruo/p/3546457.html

int nxt[maxn];
char P[maxn];
void buildNext(int &m){
    m=strlen(P+1);
    int j=0;
    nxt[1]=0;
    rep(i,2,m){
        while(j>0&&P[i]!=P[j+1]) j=nxt[j];
        if(P[i]==P[j+1])j++;
        nxt[i]=j;
    }
}
int main(){
	int t=read();
	while(t--){
		s1(P);
		int m;
		buildNext(m);
		int cir=m-nxt[m];
		if(cir!=m&&m%cir==0) println(0);//
		else println(cir-nxt[m]%cir);
	}
	return 0;
}