136. Single Number

Problem

Tags: Array, Bit Manipulation

Given a non-empty array of integers nums, every element appears twice except for one. Find that single one.

You must implement a solution with a linear runtime complexity and use only constant extra space.

Example 1:

Input: nums = [2,2,1]
Output: 1

Example 2:

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

Example 3:

Input: nums = [1]
Output: 1

Constraints:

• 1 <= nums.length <= 3 * 10^4
• -3 * 10^4 <= nums[i] <= 3 * 10^4
• Each element in the array appears twice except for one element which appears only once.

Code

JS

// 136. Single Number (6/18/53748)
// Runtime: 72 ms (83.50%) Memory: 41.32 MB (94.91%) 

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