Two Sum

twoSum.js

/**
 * @param {number[]} nums
 * @param {number} target
 * @return {number[]}
 */
var twoSum = function(nums, target) {
    let map = new Map();
    for(let i=0; i<nums.length; i++) {
        let numToFind = target - nums[i];
        if(map.has(numToFind)) return [map.get(numToFind), i];
        else map.set(nums[i], i);
    }

    return null
};

// Store the elements in a hashmap
// Start traversing the array and find (target - element at current iteration)
// If the map has the item needed, then return the current iteration value and the value found
// If not then add the value to the map and move on