Lynn Study Notes

Given a non-empty array of integers nums, every element appears twice except for one. Find that single one.

You must implement a solution with a linear runtime complexity and use only constant extra space.

Example:

Input: nums = [2,2,1]
Output: 1

Input: [4,1,2,1,2]
Output: 4

You are climbing a staircase. It takes n steps to reach the top.

Each time you can either climb 1 or 2 steps. In how many distinct ways can you climb to the top?

Example :

Input: n = 2
Output: 2
Explanation: There are two ways to climb to the top.
1. 1 step + 1 step
2. 2 steps

Input: n = 3
Output: 3
Explanation: There are three ways to climb to the top.
1. 1 step + 1 step + 1 step
2. 1 step + 2 steps
3. 2 steps + 1 step

Given a string s containing just the characters ‘(’, ‘)’, ‘{’, ‘}’, ‘[’ and ‘]’, determine if the input string is valid.

An input string is valid if:

Open brackets must be closed by the same type of brackets. Open brackets must be closed in the correct order.

雖然這個Blog是藉由GitHub Pages代管，不過像是md檔和其他資料不是說要復原就復原的，要復原還要經過一段步驟，早上實作了一次實在是搞得頭很昏，找時間在照著教學做一次並把過程記錄下來以備不時之需。

養成備份習慣是很重要的，不然資料不見了去資料救援還不一定能把資料救回來，所以我要讓我這Blog的檔案做個每日備份到雲端裡面。

首先看了一下這資料夾的檔案非常瑣碎，才93M的空間卻有14392個檔案，這樣直接備份到雲端光同步就會耗掉相當大的資源，所以我的想法是把資料夾壓縮起來再備份到雲端就好了。