求求了，来个人救救孩子吧
by qzldm @ 2022-08-31 12:45:35
```cpp
#include<iostream>
#include<algorithm>
#include<cmath>
using namespace std;
string f, m,l;
void dfs(string fr,string mi)
{
if(!fr.size()||!mi.size()) return;
int i;
for (i = 0; fr[0] != mi[i]; i++);
if (fr.size()> 1)
{
dfs(fr.substr(1, i), mi.substr(0, i));
dfs(fr.substr(i+1), mi.substr(i+1));
}
cout << fr[0];
}
int main(){
cin >> m >> f;
dfs(f, m);
return 0;
}
```
@[qzldm](/user/621493) dfs中的fr和mi可能为空串，输出fr[0]属于下标越界，特判一下即可
by FReQuenter @ 2022-08-31 13:02:50
@[FReQuenter](/user/527598) 谢谢大佬帮忙，加个if(fr.size()>0)就可以了，确实疏忽了，我好菜啊，哈哈哈
by qzldm @ 2022-08-31 15:39:01