hdu 4501 Zipper

#include<string.h>
#include<iostream>
#include<string>
using namespace std;
string s1,s2,s3;
int vist[201][201];
int dfs(int a,int b,int c)
{
    if(s3[c]=='\0') return 1; //s3搜完前提是条件都满足
    if(vist[a][b]) return 0;  //前面已经搜过了
    vist[a][b]=1;
    if(s1[a]==s3[c] && dfs(a+1,b,c+1)) return 1;
    if(s2[b]==s3[c] && dfs(a,b+1,c+1)) return 1;
    return 0;
}
int main()
{
    int t,s=1;
    cin>>t;
    while(t--)
    {
        s1.clear();
        s2.clear();
        s3.clear();
        cin>>s1>>s2>>s3;
        memset(vist,0,sizeof(vist));
        cout<<"Data set "<<s<<": ";
        s++;
        if(dfs(0,0,0))
        {
            cout<<"yes"<<endl;
        }
        else
        {
            cout<<"no"<<endl;
        }
    }
    return 0;
}