代码如下：

#include <bits/stdc++.h>
using namespace std;
char b[10], c[10];
int l;
void dfs(int left, int right){
	if (left > right){
		return;
	}
	if (left == right){
		cout << c[right];
		return;
	}
	for (int i = 0; i <= l; i++){
		if (b[i] == c[right]){
			cout << b[i];
			if (left == right - 1){
				cout << c[left];
				return;
			}
			dfs(left, i-1);
			dfs(i, right-1);
			return;
		}
	}
}
int main(){
    scanf("%s%s", b, c);
    l = strlen(c) - 1;
    dfs(0, l);
    return 0;
}

谢各位大佬 ！！！