55: Two sum

Given an array of integers and sum, return indices of numbers whose sum is equal to the given sum

Note: Each integer can be used only once and the input has exactly one solution

 

Example 1

Input: array = [2, 1, 4, 9, 0], sum = 5

Output: [1, 2]

Explanation: array[1] + array[2] = 5

Example 2

Input: array = [-2, 1, 4, 2, 10], sum = 0

Output: [0, 3]