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.
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.
For each test case, print the winning number in a line. If there is no winner, print None instead.
AC：
#include <iostream> #include <cmath> #include <vector> using namespace std; int n; struct number { int id, num; }nn; int mx = -1; bool flag = false; int arr[100000+5] = {0}, num; vector<number> v; int main() { scanf("%d", &n); for(int i = 0; i < n; i++) { scanf("%d", &num); nn.id = i; nn.num = num; v.push_back(nn); arr[num] += 1; } for(int i = 0; i < v.size(); i++) { if(arr[v[i].num] == 1) { printf("%d", v[i].num); flag = true; break; } } if(!flag) printf("None"); return 0; }刚开始打算用数字下标记录，忽略了顺序，后面改为vector，ok了
