## Tuesday, January 12, 2021

### Leetcode discuss: 2021 algorithm practice

Jan. 12, 2021

Here is the link.

I continued to work on Leetcode algorithm practice.

Dec. 30, 2020
253. Meeting Rooms II
First practice - C# - SortedSet - Challenges - +-0.1 to separate start from end time

1. Integer to English Words
First practice - C# - Check list - Take more than one hour

Jan. 5, 2021
158. Read N Characters Given Read4 II - Call multiple times
Troubleshooting - C# - "abcde", [1, 4], ["a", "bcde"] - Simulation
Working solution - C# - two lessons - variable - while or if

1. Check If a Number Is Majority Element in a Sorted Array
Jan. 5, 2021
2. Find the Kth Smallest Sum of a Matrix With Sorted Rows
First practice - C# - TLE 35/71 - DFS
Second practice - C# - copy idea - Time complexity - Each row maximum cost - Sorting

Jan. 6, 2021
839. Similar String Groups
Lesson learned - C# - Union Find - FindParent API - Union API - Failed
Second practice - C# - Union Find - Union API lesson learned

1. Best Time to Buy and Sell Stock III
C# - dynamic programming - case study - choose DP first always
C# - mock interview - performance - design issue

January 12, 2021

1. Count Good Nodes in Binary Tree
First practice - C# - Maximum value in the path
2. Employee Free Time
First practice - C# - SortedSet - Tuple<int, int, int> - challenge to make uniqueness
3. Find the Celebrity
C# - candidates - HashSet - For loop challenge
4. Reverse Nodes in k-Group
C# - Mock interview - Reverse first k nodes - recursive rest of linked list