# LeetCode - Two Sum

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 1:**

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

**Example **2**:**

```
Input: nums = [3,2,4], target = 6
Output: [1,2]
```

**Example **3**:**

```
Input: nums = [3,3], target = 6
Output: [0,1]
```

**Constraint**s** :**

- 2 <= nums.length <= 104
- -109 <= nums[i] <= 109
- -109 <= target <= 109

**Only one valid answer exists.**

** Follow-up: **Can you come up with an algorithm that is less than

`O(n`^{2})

time complexity?**Solution :**