hdu 1501 Zipper dfs

 1 #include<iostream>
 2 #include<cstdio>
 3 #include<cstring>
 4 #include<cstdlib>
 5 #include<cmath>
 6 #include<algorithm>
 7 #define inf 0x7fffffff
 8 using namespace std;
 9 const int maxn=200+10;
10 
11 int flag;
12 char s[maxn],s2[maxn],s3[maxn+maxn];
13 int vis[maxn][maxn];
14 int cnt,cnt2,cnt3,len,len2,len3;
15 
16 void dfs(int sum,int x,int y)
17 {
18     if (sum >= len3) {flag=1;return ;}
19     if (s[x]!=s3[sum] && s2[y]!=s3[sum])
20         return ;
21     if (vis[x][y]) return ;
22     vis[x][y]=1;
23     if (s[x]==s3[sum]) dfs(sum+1,x+1,y);
24     if (s2[y]==s3[sum]) dfs(sum+1,x,y+1);
25     return ;
26 }
27 
28 int main()
29 {
30     int t,ncase=1;
31     while (scanf("%d",&t)!=EOF)
32     {
33         while (t--)
34         {
35             scanf("%s%s%s",s,s2,s3);
36             len=strlen(s);
37             len2=strlen(s2);
38             len3=strlen(s3);
39             flag=0;
40             memset(vis,0,sizeof(vis));
41             if (s3[len3-1]==s[len-1]||s3[len3-1]==s2[len2-1])
42                 dfs(0,0,0);
43             if (flag) printf("Data set %d: yes\n",ncase++);
44             else printf("Data set %d: no\n",ncase++);
45         }
46     }
47     return 0;
48 }