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

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:

Sample Input 2:

5 888 666 666 888 888

Sample Output 2:

None

应该没有比这更简单的题了

 1 #include <bits/stdc++.h>
 2 
 3 using namespace std;
 4 int n;
 5 int an[100005];
 6 int vis[10005];
 7 int main(){
 8     cin >> n;
 9     for(int i = 0; i<n; i++){
10         cin >> an[i];
11         vis[an[i]]++;
12     }
13     for(int i = 0; i < n; i++){
14         if(vis[an[i]] == 1){
15             cout << an[i] << endl;
16             return 0;
17         }
18     }
19     cout <<"None"<<endl;
20     return 0;
21 }