Being unique is so important to people on Mars that even(甚至) their lottery(彩票) is designed in a unique way. The rule of winning is simple(简单的): 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
AC代码
#include <iostream>
#include <vector>
#include <unordered_map>
using namespace std;
int main()
{
vector<int >a;
unordered_map<int,int>b;
int n,temp;
cin>>n;
for(int i=0;i<n;i++)
{
cin>>temp;
a.push_back(temp);
b[temp]++;
}
bool flag=false;
for(int i=0;i<a.size();i++)
{
if(b[a[i]]==1)
{
cout<<a[i];
flag=true;
break;
}
}
if(!flag)
cout<<"None";
return 0;
}