136.Single Number.md

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136. Single Number

Easy

https://leetcode.com/problems/single-number/submissions/

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

解题：异或 ^

/**
 * @param {number[]} nums
 * @return {number}
 */
var singleNumber = function(nums) {
    let reg = 0
    for(let i = 0; i < nums.length; i ++) {
        reg = reg ^ nums[i]
    }
    return reg
};