题解 | #提取不重复的整数#

#include <iostream>
#include <bits/stdc++.h>
using namespace std;


int main(){
    int n;
    cin >> n;
    string str = to_string(n);
    unordered_set<char> set;
    reverse(str.begin(),str.end());
    string res;
    for (char c:str){
        if (set.count(c) != 1)
        {
            res += c; 
            set.insert(c);
        }
    }
    cout << stoi(res) << endl; 
}