[leetcode]136. Single Number

Given a non-empty 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?

Example 1:

Input: [2,2,1]
Output: 1
Example 2:

Input: [4,1,2,1,2]
Output: 4

Solution：

class Solution {
    public int singleNumber(int[] nums) {
        int len = nums.length;
        int xor = nums[0];
        for(int i = 1; i < len; i++) {
            xor ^= nums[i];
        }
        return xor;
    }
}