solution

• 目标数：出现次数为奇数次&&该数本身为奇数

#include<iostream>
using namespace std;
const int maxn = 1e5 + 10;
int flag[maxn] = {0};
int main(){int n, x;scanf("%d", &n);for(int i = 1; i <= n; i++){scanf("%d", &x);flag[x]++;}for(int i = 1; i < maxn; i += 2){if(flag[i] % 2 == 1){printf("%d", i);break;}}return 0;
}