【Everyday】(16)落单的数到位运算 - Everyday - SegmentFault



【Everyday】(16)落单的数到位运算 - Everyday - SegmentFault

给出2*n + 1 个的数字,除其中一个数字之外其他每个数字均出现两次,找到这个数字。

样例
给出 [1,2,2,1,3,4,3],返回 4

挑战
一次遍历,常数级的额外空间复杂度

解题思路

找到落单数字,一个很笨的方法,开一个很大的数组,然后遍历之后,记录下来,然后再遍历一遍,进一步提升的方法是借助于位运算,其它的数均出现两次,想到位运算中,两个相同的数字通过异或运算之后为零,所以将其遍历一次进行异或运算,最后得出的数字即为我们所要求的落单数字。


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