1041 Be Unique (20分)(水)

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

 #define _CRT_SECURE_NO_WARNINGS
 #include <climits>
 #include<iostream>
 #include<vector>
 #include<queue>
 #include<map>
 #include<set>
 #include<stack>
 #include<algorithm>
 #include<string>
 #include<cmath>
 using namespace std;
 int num[];
 int main()
 {
     int N;
     cin >> N;
     vector<int> V(N);
     int n = -;
     for (int i = ; i < N; i++)
     {
         cin >> V[i];
         num[V[i]]++;
     }
     for (int i = ; i < N; i++)
     {
         if (num[V[i]] == )
         {
             n = i;
             break;
         }
     }
     if (n != -)
         cout << V[n];
     else
         cout << "None";
 }