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 (≤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
分析
本题考查map以及STL的应用,属于简单题
#include <iostream>
#include <map>
#include <vector>
using namespace std;
int a[10010];
int main(){
int n;
cin>>n;
vector<int> v(n);
for(int i=0;i<n;i++) {
cin>>v[i];
a[v[i]]++;
}
for(auto it :v){
if(a[it]==1){
cout<<it<<endl;
return 0;
}
}
cout<<"None"<<endl;
return 0;
}