KMP

#include<iostream>#include<cstdio>#include<cstring>#include<string>#include<vector>#include<algorithm>using namespace std;int nxt[10009],l1,l2;char s1[100009],s2[10009];void next_make()//求nxt数组{    int t1=0,t2=-1;    nxt[0]=-1;    while(t1<l2)    {        if(t2==-1||s2[t1]==s2[t2])        {            nxt[++t1]=++t2;        }        else t2=nxt[t2];    }}void match(int t1,int t2){    while(t1<l1&&t2<l2)    {        if(t2==-1||s2[t2]==s1[t1])          t1++,t2++;        else           t2=nxt[t2];           }    if(t2==l2)    {        printf("YES\n");        return;    }    printf("NO\n");    return;}int main(){    gets(s1);gets(s2);    l1=strlen(s1);    l2=strlen(s2);    next_make();    match(0,0);    return 0;}