C :

#include"stdio.h"
#include"string.h"
int main()
{
    char a[1000],b[1000],c[1000];
    int n,i,j,k,count=1,len,flag;
    scanf("%d",&n);
    while(n--)
    {
          flag=0;
          scanf("%s%s%s",a,b,c);
          len=strlen(c);
          for(i=0,j=0,k=0;k<len;k++)
          {
              if(c[k]==a[i]) i++;
              else if(c[k]==b[j])  j++;
              else {
                      flag++;
                      break;
                   }   
          } 
          for(i=0,j=0,k=0;k<len;k++)
          {
              if(c[k]==b[j]) j++;
              else if(c[k]==a[i])  i++;
              else {
                      flag++;
                      break;
                   }   
          }   
          printf("Case %d: ",count++);
          if(flag==2)
          printf("no\n");
          else
          printf("yes\n");  
    }
}

C++ :

#include <stdio.h>
#include <string.h>

int main() {
	int n, dp[201][201], i, j, la, lb, C = 0;
	char a[201], b[201], c[402];
	scanf("%d", &n);
	while (n--) {
		scanf("%s%s%s", a, b, c);
		memset(dp, 0, sizeof(dp));
		la = strlen(a);
		lb = strlen(b);
		for (i = 0; i < la; i++) {
			if (a[i] == c[i])
				dp[i + 1][0] = 1;
			else
				break;
		}
		for (i = 0; i < lb; i++) {
			if (b[i] == c[i])
				dp[0][i + 1] = 1;
			else
				break;
		}
		for (i = 1; i <= la; i++)
			for (j = 1; j <= lb; j++)
				if ((dp[i - 1][j] && a[i - 1] == c[i + j - 1]) || (dp[i][j - 1]
						&& b[j - 1] == c[i + j - 1]))
					dp[i][j] = 1;
		printf("Case %d: ", ++C);
		puts(dp[la][lb] ? "yes" : "no");
	}
	return 0;
}

Java :

import java.util.Scanner;
class deal{
	public int n,m;
	public char [] one,two,comb;
	public int flag[][]=new int[210][210];
	public deal(){}
	public void init(String...all){
		one=all[0].toCharArray();
		two=all[1].toCharArray();
		comb=all[2].toCharArray();
		n=all[0].length();
		m=all[1].length();
		for(int i=0;i<n+5;i++)
		{
			for(int j=0;j<m+5;j++)flag[i][j]=0;
		}
	}
	public boolean solve(int i,int j,int k){
		if(i>=n && j>=m)return true;
		if(flag[i][j]==1)return false;
		boolean f=false;
		if(i<n)
		{
			if(one[i]==comb[k])
			{
				f=solve(i+1,j,k+1);
				if(f)return f;
			}
		}
		if(j<m)
		{
			if(two[j]==comb[k])
			{
				f=solve(i,j+1,k+1);
				if(f) return f;
			}
		}
		flag[i][j]=1;
		return false;
	}
}
public class Main{
	public static void main(String...strings)
	{
		Scanner in = new Scanner(System.in);
		int t=in.nextInt();
		deal h = new deal();
		int T=0;
		while(T<t)
		{
			T++;
			System.out.print("Case "+T+": ");
			h.init(in.next(),in.next(),in.next());
			if(h.solve(0,0,0))System.out.println("yes");
			else System.out.println("no");
		}
	}
}