基础题，主要思路是找到根，然后分别递归即可；
1 #include<iostream> 2 #include<cstring> 3 #include<string> 4 #include<cstdio> 5 #include<cstdlib> 6 using namespace std; 7 char s[30],t[30]; 8 int n; 9 void dfs(int x,int y,int a,int b){ 10 int k; 11 for(int i=a;i<=b;i++)if(s[i]==t[x]){k=i;break;} 12 if(k!=a)dfs(x+1,x+k-a,a,k-1); 13 if(k!=b)dfs(x+k-a+1,y,k+1,b); 14 cout<<t[x]; 15 } 16 void work(){ 17 scanf("%s%s",s,t); 18 n=strlen(s); 19 dfs(0,n-1,0,n-1); 20 } 21 int main(){ 22 freopen("1.in","r",stdin); 23 freopen("1.out","w",stdout); 24 work(); 25 }