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 (≤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

超时版本

#include 
#include 
using namespace std;
int main()
{
    int n;
    cin >> n;
    int v[100001];
    int flag;
    for(int i=0;i> v[i];
    }
    for(int j=0;j

正确版本

#include 
#include 
using namespace std;
int main()
{
    int v[100001],cnt[10001];
    int n;
    cin >> n;
    for(int i=0;i> v[i];
        cnt[v[i]]++;
    }
    for(int i=0;i