HDU 2095

      做了一下HDU  的2095 题。开始一直都不会。后来就百度了一下。看到的大都是将所有输入的数异或一下。然后得到的最后结果就是要输出的结果。但是我还是没能理解！然后就又反复得看了一下题目要求。

     

　　

In the new year party, everybody will get a "special present".Now it's your turn to get your special present, a lot of presents now putting on the desk, and only one of them will be yours.Each present has a card number on it, and your present's card number will be the one that different from all the others, and you can assume that only one number appear odd times. For example, there are 5 present, and their card numbers are 1, 2, 3, 2, 1.so your present will be the one with the card number of 3, because 3 is the number that different from all the others.

　　题目中，这句话说得那是一个有意思啊。" 你的礼物卡片上的数据是所有数据中唯一只有一个的而且不同与其他数据的数 "。所以呢，当将所有的数据进行异或的时候。那些相同的数据就异或之后为 0 ，比如7 ^ 7 = 0 .而你自己的那个呢是个"单身汉"，其他的所有数据异或完后就只剩下一个 0 ，"单身汉" ^ 0 = "单身汉"。

所以代码如下：

#include <stdio.h>

int main()
{
	int n,fact,m;
	while(scanf("%d",&n) && n)
	{
		fact = 0;
		while(n--)
		{
			scanf("%d",&m);
			fact^=m;
		}
		printf("%d\n",fact);
	}
	return 0;
}

转载于:https://www.cnblogs.com/nicolase/archive/2010/11/20/1882671.html