题解 | #提取不重复的整数#

#include<bits/stdc++.h>
using namespace std;
int main() {
    int nums;
    cin >> nums;
    string str = to_string(nums);
    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;
    return 0;
}