The idea to create a campaign is here.
2018-August

It is always good to push yourself to think hard and aim the optimal solution in terms of time complexity. Last Thursday I had chance to work on the algorithm called "construct a binary expression tree using infix expression" in 30 minutes. Since I do not take risk to go for the optimal solution using O(N) and stack data structure, I learn the lesson again.

I like to start to put together 100 hard level algorithms practice and learning here. Those hard level algorithms change my life as a sofware programmer. I need to get organized and also strive to think more often for those hard level algorithms.

A
B
C

D
Deletion distance

E
F
G
H

I
Infix expression to binary expression tree

J
K
L
M
N
O

P
Pigeon hole principle

Q

R
Regular expression matching

S
Sliding window
Sliding window maximum
Sliding windows minimum
Sudoku solver

T
U
Union find algorithm and practice March 26, 2019
V
W
X
Y
Z

2019-03-26
It is so interesting to learn the lesson again. I have to spend more time to work on union find algorithm, since I could not find one copy of code called UnionFind class which is trustable. And secondly I do not get familiar with APIs.
I need to memorize all APIs first.
I need to learn how to analyze the time complexity as well.
I need to practice to write a solution based on union find algorithm, and finish it in 45 minutes.
I need to work on the algorithm once a week, once a month, or once a three months.
Union find algorithm One lesson a time

2020 April 3
I have a break to work on personal finance research, and then investment on stock market. But I always continue to interview as an interviewer on interviewing.io last six months. I start to build more connections to people, and understand how to write bug free code. The crafting skills should include the talent to consider all edge cases and make my own approach bug-free, less time like 10 to 20 minutes.

I like to add those algorithms to my repository. Those are marked with medium or easy level sometimes.

Leetcode 33 search in rotated sorted array mock interviews as an interviewer from March - April 2020

Leetcode 958 check completeness of binary tree mock interviews as an interviewer from March - April 2020