题解 | #图片整理#

异或，专业找单身数

#include<stdio.h>
int main()
{
    int n = 0;
    int num = 0;
    int ret = 0;
    scanf("%d",&n);
    for(int i = 0; i < n; ++i)
    {
        scanf("%d",&num);
        ret ^= num;
    }
    printf("%d",ret);
}