# 1436 Destination City

## Problem Statement

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

**, and you may not use the**

*exactly*one solution*same*element twice.

You can return the answer in any order.

**Input:**nums = [2,7,11,15], target = 9

**Output:**[0,1]

## Approach

The BF solution would be to compare each element with each other element and see if they match the target. This approach is very inefficient with a BigO(N²) due to two nested for loops.

The recommended solution is to use a hashmap and check if target - current number is in the hashmap, if so return if not add the entry at i.

## Solution

```
var twoSum = function(nums, target) {
let hash = {}
for (let i=0; i < nums.length; i++){
if ((target - nums[i]) in hash){
return [i, hash[target - nums[i]]]
}
hash[nums[i]] = i
}
};
```