Two Sum – LC1 JS Solution

🔗LC1 🟢 Easy 🧩 Pattern – Hashtable and Array

Given an array of integers nums and an integer target, return indices of the two numbers such that they add up to target.

You may assume that each input would have exactly one solution, and you may not use the same element twice.

You can return the answer in any order.

Example

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

Input: nums = [3,2,4], target = 6
Output: [1,2]Code language: JavaScript (javascript)

Solution

We use a single loop iteration to find the next value based on the current number, current number = 6; target = 9; then requiredNumber = 9-6 = 3, if 3 already exists in the map then we return both their indices.

/**
 * @param {number[]} nums
 * @param {number} target
 * @return {number[]}
 */
var twoSum = function (nums, target) {
    const memory = new Map();
    for (let index = 0; index < nums.length; index++) {
        const currentNumber = nums[index];
        const requiredNumber = target - currentNumber;
        if (memory.has(requiredNumber)) {
            return [memory.get(requiredNumber), index];
        } else {
            memory.set(currentNumber, index);
        }
    }
};Code language: JavaScript (javascript)

Back to Top