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 [1,104]. 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 (≤105) 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<bits/stdc++.h>
using namespace std;
int main(){
    int n;
    cin>>n;
    int bet[100005];
    int count[10005]={0};
    bool flag=false;
    for (int i=0;i<n;++i){
        cin>>bet[i];
        count[bet[i]]++;
    }
    for (int i=0;i<n;++i){
        if (count[bet[i]]==1){
            cout<<bet[i];
            flag=true;
            break;
        }
    }
    if(!flag){
        cout<<"None";
    }
}