[Leetcode] 1. Two Sum

完整題目: 1. Two Sum Easy

• Given an array of integersnums 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]

1. 暴力解O(n²)

使用2個for迴圈，如果有遇到2個數加起來等於target，則回傳index

2. NeetCode解法

參考影片 : https://www.youtube.com/watch?v=KLlXCFG5TnA