PAT 甲级 1041 Be Unique （20 分）

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 [1,10​4​​]. 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 (≤10​5​​) 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>
 #include<map>

 using namespace std;

 int main()
 {
     int N, temp, index = , min = ;
     map<int, int> m;

     cin >> N;

     for (int i = ; i<N; ++i)
     {
         cin >> temp;

         if (m.find(temp) == m.end())
             m.insert(pair<int, int>(temp, index++));
         else
             m[temp] = ;
     }

     map<int, int>::iterator begin = m.begin(), end = m.end(), i, minIndex;

     for (i = begin; i != end; ++i)
     {
         if (i->second> && i->second<min)
         {
             min = i->second;
             minIndex = i;
         }
     }

     if (min == )
         cout << "None" << endl;
     else
         cout << minIndex->first << endl;
 }