HDU 1501 Zipper(dfs)

Posted 2020-06-10

Zipper Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others) Total Submission(s): 8580    Accepted Submission(s): 3028     Problem Description Given three strings, you are to determine whether the third string can be formed by combining the characters in the first two strings. The first two strings can be mixed arbitrarily, but each must stay in its original order.   For example, consider forming "tcraete" from "cat" and "tree":   String A: cat String B: tree String C: tcraete     As you can see, we can form the third string by alternating characters from the two strings. As a second example, consider forming "catrtee" from "cat" and "tree":   String A: cat String B: tree String C: catrtee     Finally, notice that it is impossible to form "cttaree" from "cat" and "tree".     Input The first line of input contains a single positive integer from 1 through 1000. It represents the number of data sets to follow. The processing for each data set is identical. The data sets appear on the following lines, one data set per line.   For each data set, the line of input consists of three strings, separated by a single space. All strings are composed of upper and lower case letters only. The length of the third string is always the sum of the lengths of the first two strings. The first two strings will have lengths between 1 and 200 characters, inclusive.       Output For each data set, print:   Data set n: yes   if the third string can be formed from the first two, or   Data set n: no   if it cannot. Of course n should be replaced by the data set number. See the sample output below for an example.     Sample Input 3 cat tree tcraete cat tree catrtee cat tree cttaree     Sample Output Data set 1: yes Data set 2: yes Data set 3: no     Source Pacific Northwest 2004

 

 

 1 #include <iostream>
 2 #include <cstdio>
 3 #include <cstring>
 4 using namespace std;
 5 const int maxn=1010;
 6 bool v[maxn][maxn];
 7 int f=0;
 8 int l1,l2,l3;
 9 char a[maxn],b[maxn],c[maxn];
10 void dfs(int x1,int x2,int x3)
11 {
12     if(x3>=l3) {
13         f=1;
14         return ;
15     }
16     if(f==1) return ;
17     if(v[x1][x2]) return ;
18     if(a[x1]==c[x3]) dfs(x1+1,x2,x3+1);
19     if(b[x2]==c[x3]) dfs(x1,x2+1,x3+1);
20     v[x1][x2]=1;
21 }
22 int main()
23 {
24     int n;
25     cin>>n;
26     for(int i=1;i<=n;i++){
27         cout<<"Data set "<<i<<": ";
28         scanf("%s%s%s",a,b,c);
29         memset(v,0,sizeof(v));
30         l1=strlen(a);
31         l2=strlen(b);
32         l3=strlen(c);
33         if(l1+l2!=l3){
34             cout<<"no"<<endl;
35             continue;
36         }
37         else{
38             f=0;
39             dfs(0,0,0);
40             if(f==0) cout<<"no"<<endl;
41             else cout<<"yes"<<endl;
42         }
43     }
44     return 0;
45 }