# Leetcode: Two Sum (JS)

Example 1:

`Input: nums = [2,7,11,15], target = 9Output: [0,1]Explanation: Because nums + nums == 9, we return [0, 1].`

Understanding the problem:

Per the example above, if we start with 2, and we want to reach 9 — we need to add 7 from the array. The indices for 2 and 7 are 0 and 1.

How do we do this?

`function twoSum(nums, target){// a map that holds the numbers and their indices  let numberIndex = new Map();// we need an array for our indices results  let result = [];// loop through the nums array  for (let i=0; i < nums.length; i++){//current element we're on     let currentNum = nums[i];// save the difference between the number we're on and the target     let neededNum = target - currentNum;// check to see if the map has the number we need     if (numberIndex.has(neededNum)){        result = numberIndex.get(neededNum);        result = i;        return result;  }     //if they don't match, add the current number & index to the map     numberIndex.set(currentNum, i)}// return our indices resultsreturn result;}`

Another Solution:

`function twoSum(nums, target){// a map that holds the numbers and their indiceslet map = new Map(); // loop through the nums array  for (let i = 0; i < nums.length; i++){//current element we're on    let currentNum = nums[i];// save the difference between the number we're on and the target    let neededNum = target — currentNum;// check to see if the map has the number we need        if (map.has(neededNum)){// return our indices results        return [i, map.get(neededNum)]; }//if they don't match, add the current number & index to the map     map.set(currentNum, i); }`

✨✨✨And that’s it!

Tish⚡️🎧🌙