题解 | #找出字符串中第一个只出现一次的字符#

#include <iostream>
#include <vector>
using namespace std;

int main() {
    string s;
    int min=1001;
    int count = 1;
    char res ;
    vector<int> store(26,0);
    getline(cin,s);
    for(int i = 0;i<s.size();i++){
        if(store[s[i]-'a']==0){
            store[s[i]-'a'] = count;
            count++;
            continue;
        }if(store[s[i]-'a']!=0){
            store[s[i]-'a']=-1;
            count++;
            continue;
        }
        
    }
    for(int i = 0;i<26;i++){
        if(store[i]<min){
            if(store[i] == 0 || store[i] == -1){
                continue;
            }else{
                min = store[i];
                res = 'a'+i;
            }
        }
    }
    if(min == 1001){
        cout<<"-1";
    }else{
        cout<<res;
    }
}
// 64 位输出请用 printf("%lld")