Leetcode problem- TwoSum

I like to solve some leetcode problems and see how much faster they can be made. Today, we are solving the TwoSum problem. Below are two of the solutions.

Problem: https://leetcode.com/problems/two-sum/description/

Solution 1 — Runs in 35 ms — O(n²) time complexity

/**
 * @param {number[]} nums
 * @param {number} target
 * @return {number[]}
 */
var twoSum = function(nums, target) {
    let map = {};

    for (let i = 0; i < nums.length; i++) {
        let needed = target - nums[i];

        if (map[needed] !== undefined) {
            return [map[needed], i];
        } else {
            map[nums[i]] = i;
        }
    }

    return [];
};

Solution 2 — Runs in 1 ms — O(n) time complexity

/**
 * @param {number[]} nums
 * @param {number} target
 * @return {number[]}
 */
var twoSum = function(nums, target) {
    let map = {};

    for (let i = 0; i < nums.length; i++) {
        let needed = target - nums[i];

        if (map[needed] !== undefined) {
            return [map[needed], i];
        } else {
            map[nums[i]] = i;
        }
    }

    return [];
};

It feels so good when your solution becomes faster!!!

And the happiness feeling. Little drops of joy!