题目描述
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
代码
#include <iostream>
#include <vector>
using namespace std;
int book[10001];
int main() {
int n, flag = 0;
scanf("%d", &n);
vector<int> b(n);
for (int i = 0; i < n; i++) {
cin >> b[i];
book[b[i]]++;
}
for (int i = 0; i < n; i++) {
if (book[b[i]] == 1) {
printf("%d", b[i]);
return 0;
}
}
printf("None");
return 0;
}
