[Leetcode]1 : Two Sum

Link : https://leetcode.com/problems/two-sum/

Problem :
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.


Thoughts :
1. 一開始沒有想到要用enumerate,可以同時取用到 key 跟 value。
2. 跑迴圈,並透過與target相減的方式來獲得需要的資訊。
3.在return的時候需要注意如何取得 key。

Solution :

time complexity, space complexity

follow up question:
4-worse case?



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