hdu 2203 亲和串

题意：给定两个字符串s1和s2,如果能通过s1循环移位，使s2包含在s1中，那么我们就说s2 是s1的亲和串。

题解：把第一个字符串扩展为2倍，然后kmp

#include <cstdio>
#include <iostream>
#include <cstring>
#include <string>
#include <cmath>
#include <set>
using namespace std;
const int maxn = 100005;
char s[2*maxn],s1[maxn],s2[maxn];
int len,len1,Next[maxn];
void Get_next()
{
    int i = 0,j = -1;
    Next[0] = -1;
    while(i < len1)
    {
        if(j == -1 || s[i] == s1[j])
        {
            i++;
            j++;
            Next[i] = j;
        }
        else
            j = Next[j];
    }
}
int kmp()
{
    int i = 0,j = 0,flag = 0;
    while(i < len)
    {
        if(s[i] == s1[j] || j == -1)
        {
            i++;
            j++;
            //printf("%d %d\n",i,j);
        }
        else
        {
           // printf("%d\n",j);
            j = Next[j];

        }
        if(j == len1)
        {
            flag = 1;
            break;
        }
        //printf("%d %d\n",i,j);
    }
    return flag;
}
int main()
{
    int t,c = 1;
    while(scanf("%s%s",s,s1) == 2)
    {
        len = strlen(s);
        len1 = strlen(s1);
        if(len < len1)
        {
            printf("no\n");
            continue;
        }

        for(int i = len; i < len * 2; i++)
            s[i] = s[i-len];
        len *= 2;

        Get_next();
        printf("%s\n",kmp() == 1? "yes" : "no");
    }
    return 0;
}