/**

* @link https://leetcode.com/problems/two-sum/

* @description Return indices of the two numbers such that they add up to target.

* @param {Object []} nums

* @param {Number} target

* @returns {Object []}

*/

export default (nums, target) => {

// key: Number that adds up to target

// value: Index the number is at

const twoSum = {};

// Iterate through nums using indices b/c we need the indices

// for the final ads

for (let i = 0; i < nums.length; i += 1) {

const currentNumber = nums[i];

// Case 1: We found a pair that adds up to target

if (currentNumber in twoSum) {

return [twoSum[currentNumber], i];

}

// Case 2: Add a new entry for the current number

twoSum[target - currentNumber] = i;

}

// If we go through the entire for loop without returning

// there's no valid answe

return -1;

};