题解 | #删除字符串中出现次数最少的字符#

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

int main() {
    string s;
    cin >> s;
    
    unordered_map<char, int> my_map;
    for (int i = 0; i < s.size(); i++) {
        my_map[s[i]]++;
    }
    int min = INT_MAX;
    for (auto it = my_map.begin(); it != my_map.end(); it++) {
        if (it->second < min) {
            min = it->second;
        }
    }
    unordered_set<char> delete_set;
    for (auto it = my_map.begin(); it != my_map.end(); it++) {
        if (it->second == min) {
            delete_set.insert(it->first);
        }
    }
    for (int i = 0; i < s.size(); ) {
        if (delete_set.find(s[i]) != delete_set.end()) {
            s.erase(i, 1);
        } else {
            i++;
        }
    }
    cout << s << endl;

    return 0;
}