Two Sum — Easy Coding Interview Question

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].

Constraints

• 2 ≤ nums.length ≤ 10⁴
• -10⁹ ≤ nums[i] ≤ 10⁹
• -10⁹ ≤ target ≤ 10⁹
• Only one valid answer exists.

Topics & Companies

Topics: arrays, hash-map

Asked by: Amazon, Google, Meta, Microsoft, Apple, Bloomberg, Uber

Optimal Solution Complexity

Time complexity: O(n). Space complexity: O(n).

Practice more

• All DSA Problems
• DSA Patterns