A1050 String Subtraction

题目：https://pintia.cn/problem-sets/994805342720868352/problems/994805429018673152
这题用string的find函数就超水～

代码

#include<iostream>
#include<vector>
#include<string>
#include<algorithm>
using namespace std;
int main(){
    string s1,s2;
    getline(cin, s1);
    getline(cin, s2);
    for(int i = 0; i < s1.size(); i++){
        if(s2.find(s1[i])==string::npos){
            cout<<s1[i];
        }
    }
}