PAT Advanced 1041 Be Unique (20 分)

Being unique is so important to people on Mars that even their lottery is designed in a unique way. The rule of winning is simple: one bets on a number chosen from [1]. The first one who bets on a unique number wins. For example, if there are 7 people betting on { 5 31 5 88 67 88 17 }, then the second one who bets on 31 wins.

Input Specification:

Each input file contains one test case. Each case contains a line which begins with a positive integer N (≤) and then followed by N bets. The numbers are separated by a space.

Output Specification:

For each test case, print the winning number in a line. If there is no winner, print None instead.

Sample Input 1:

7 5 31 5 88 67 88 17

Sample Output 1:

31

Sample Input 2:

5 888 666 666 888 888

Sample Output 2:

None

#include <iostream>
using namespace std;
int main(){
    int T;
    cin>>T;
    int va[T],coun[10001];
    for(int i=0;i<T;i++){
        scanf("%d",&va[i]);
        coun[va[i]]++;
    }
    bool has=false;
    for(int i=0;i<T;i++){
        if(coun[va[i]]==1) {
            cout<<va[i];
            has=true;
            break;
        }
    }
    if(!has) cout<<"None";
    system("pause");
    return 0;
}