leetcode-Single Number

Given an array of integers, every element appears twice except for one. Find that single one.

Note:
Your algorithm should have a linear runtime complexity. Could you implement it without using extra memory?

 

能夠巧妙地運用XOR運算符，由於兩個相同的數字XOR以後會被消除影響，因此剩下的就是惟一存在的數字。