题解 | #找出字符串中第一个只出现一次的字符#

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

int main() {
    string str;
    getline(cin, str);
    int symbol =0;
    for (int i = 0; i < str.length(); i++) {
        int count =0;
        if (i == str.length() - 1) {
            for (int j = 0; j < str.length() - 1; j++) {
                if (str[i] == str[j]) {
                    count =1;
                    break;
                }
            }
            if (count == 0) {
                cout << str[i] << endl;
                symbol =1;
            }
        } 
        else {
            for (int j = str.length() -1; j >=0 && j != i; j--) {
                if (str[i] == str[j]) {
                    count =1;
                    str.erase(j,1);
                }
            }
            if (count == 0) {
                cout << str[i] << endl;
                symbol =1;
                break;
            }
        }
    }
    if(symbol ==0){
        cout << -1 << endl;
    }
}