Celebration of 289 algorithms solved

Nov. 2, 2018

Introduction

It is challenging to write a blog using this topic "289 algorithms". I like to spend ten minutes to write a story about it. I just solved 289 algorithms on Leetcode.com. It is time for me to celebrate and then I like to write down my thought process to achieve this goal.

289 vs 100

I have been worked on Leetcode since January 2015, I started to work on algorithms on Leetcode.com and then learned so many ways to improve myself. I think that the learning experience is valuable, but one thing is missing. I only completed around 100 algorithms after three years six months.


Last four months, I started to work on algorithms. I always try to find easy level algorithms first. I like to solve more problems. Now today I solved 289 algorithms.

I still have over 20 easy level algorithms to work on. Those algorithms are bit manipulation, and other things.

Why number matters?

It is hard for me to measure myself; I have to journal my practice and then I found out that I do not know what it matters most. It is the number of algorithms I solve. I need to get those experience as top 5% players does. Top 5% is related to ranking 3300 out of 70,000 player.


I read a player with over 5466 submissions, and I did read Javascript submissions. I have to think about how I can find time to work on my JavaScript, my favorite language.

Here is my blog related to leetcode book.

The following is the comparison. A player knows to solve more algorithms, and also more than 5,000 submissions. My profile is the right side, with 289 solved algorithm, 1039 submissions. The player has more than 4400 submissions and solved more than 245 algorithms.

The medium level algorithms are my playground, I do not plan to get any interview right now in next 20 months. I just like to explore those algorithms and find something interesting to work on.

Blogging is just the beginning

It is the tip I learn from tennis sports coaching. Journal your practice. But blogging is just the beginning, after three years six months blogging starting from January 2015, I found out that I did not make enough progress in terms of problem solving skills.

I had to take a private coach in June 2018, and then got his advice on working on easy level algorithms first. I did not have strong competitive history and it makes me hard to figure out what is the next.

I have to work on those numbers, number of solved algorithm, total submissions, and I have to work hard to get more experience through those algorithms on Leetcode.com platform. 

Celebrate of 277 submissions on Leetcode in the last year

Sept. 3, 2018

Introduction

It is 10:21 PM, and I like to write a small research talk. It is called to celebrate 277 submissions. I had 277 submission in the last year on Leetcode.com, I found one role model with 1300 submission in the last year.

Let us visualize the data

Here is my profile up to Sept. 3, 2018.

I know that it took me a lot of hours to finish 277 submissions. I did most of work last two months. 

Here is my role model, the profile is here. Ranking is 2086. Solved algorithm: 570/893

Actionable items

I have good time to work on easy level array algorithm on Leetcode.com today, but I also learn a few things through the study. 

I worked on easy level algorithm. One algorithm usually takes one submission. But tianyuan worked on medium level or hard level, one hard level algorithm took 4 submissions, one medium level took 7 submissions. 

So I will expect more submission after I finish another 120 easy level algorithms first. 

I miss the joy to work on medium level and hard level algorithms. I know that it is better for me to work on easy level algorithms, and get used to write code every day first. 

Here is the snapshot with a person over 570 solved problems, how the training looks like. 

  

Celebration of 960 submissions

Oct. 17, 2018

Introduction

It is time for me to learn how to be a nice player and say thanksgiving to my coach this June. I had chance to find my weakness, I need to work on easy level algorithms first.

After I solved 160 easy level algorithm, I had chance to celebrate 960 submssions on Leetcode.com.

Get smarter

It is easy to get smarter once I learn from my past 300 submissions. I solved 160 easy level algorithms last three months, I had over 300 submissions.

I started from January 2015. From 2015 to June 2018, I only has submissions on Leetcode.com less than 600.

I need to learn those players, every year with over thousand submissions. Without taking any course, any cost of tuition, one player can learn how to write good program through those Leetcode.com algorithms.

One thing I like to do is to take easy level algorithms first. And also I need to learn that it is important for me to build good  habit to write code everyday.

Submissions

I learn to read other people's profile by checking total submissions.

Here is mine.

Here is my role model with over 2800 submissions. The role model solved over 800 algorithms.

What is difference from mine, 260 solved algorithm, 900 submissions. There are  more than 540 algorithms, more than 1900 submissions. Each contest on Leetcode.com has 4 algorithms, so 540 algorithms can be used almost 150 weekly contest algorithms.

In other hand, every onsite interview from Faceook or Amazon, the interviewee will work on 4 algorithms. The extra practice is like a player having more than 100 onsite interviews experience from various software companies, all of those are very focusing on algorithm and data structure as well.

celebration of 150 mark - I solved 150 Leetcode algorithms

August 14, 2018

Introduction

It is time for me to celebrate 150 solved algorithm on Leetcode.com. I like to celebrate the mark of 150 solved algorithm. Last two months I solved 50 algorithms.

Motivations 

I like to write down motivations I had in order to complete extra 50 level algorithms in less than two months.

How to perform best onsite on algorithm?

June 21, 2018

Introduction

It is true that I have over 300 interviews last 12 months. But in terms of real one, I understand that I only have one this year. How to push myself hard to come out a solution for those 20 minutes?

Think about scalability

It is wise to follow the hackerrank contest format. Set up time limit to 3 seconds, set up upper bound for those given variables, for example, sort a array in two dimension, I can talk about Rows <= 1000, Cols <= 1000, or given 1000,000 instead of 1000. And then I like to target the time complexity based on Rows * Cols, linear or power of 2, preprocessing time for those number, what is space minimum I need. Calculate one in terms of MB. Usually hackerrank space is limited to 300MB.

Try to guess what is limit? Ask and then figure out possible upper bound of time complexity.

I think that will be good start for an onsite and real top one software company.

I stopped playing hackerrank since November 2017. I totally forget those painful and long hours I have worked to try to gain extra few points to scale the problem. I will give one example here later on.

Get organized

Last few days I tried to get organized and checked in past contests into github, I like to review C# code I write before. And then I notice something missing in my daily practice last 8 months. I focus on soft skills, but I lose the desire to scale the algorithm problem.

Follow up 

March 28, 2019

I like to try the idea to work on algorithm problem solving 90 minutes every day. And I like to see how many problems I can solve in one week.

Another thing is to solve all 24 union join algorithm on Leetcode.com first. I need to push myself to learn and work on algorithm daily.

Another thing I can try to do is to get involved in video creating for the algorithm.

Another thing I can try to push myself is to complete another 100 algorithms before June 6, 2019. I like to celebrate one year Amazon onsite with Leetcode solved problems 470 or 500. I think that hard working is most important part of my life.

Celebration of 200 solved algorithms on Leetcode.com

Sept. 5, 2018

Introduction

It is time for me to celebrate 200 solved algorithm on Leetcode.com. I am getting smart to work on my goal, solve more algorithms.

I also learn to prepare a page on my github called Leetcode discuss.

It is such great journey to work on easy level algorithms. So many things I learned from my practice on Add strings algorithm.

Get it done, two more algorithms

I still have to work on two more algorithms in order to reach 200. I like to share my last few math algorithms with submissions. I am proud of myself to prepare myself, train myself.

Leetcode 317: Shortest distance from all buildings (Part 4)

Feb. 16, 2017

Introduction

Julia was trying to find a good one to ask code review on stackexchange.com, and the she noticed that her blog is coming to a landmark 100,000 views. So, she likes to celebrate her hard work, she saw one of visitor was from search result using keyword: Leetcode 317 in last 7 days. So, the user of the blog solved her problem - find a nice algorithm to review. She worked on the algorithm before, she did twice. 

Her first practice is more than 12 months, she reviewed the blog in January 2016. In May 11, 2016, she practised again the algorithm. Her practice code is here. Through her practice, she likes to track her progress. She likes to say just so so, coding is like tennis sport, she has to learn from best - Roger Federer.

Workout

Julia likes to rewrite the C# code based on last practice in January, 2016. And here are the highlights of change.

To challenge herself, she designed several classes to track intermediate result, for example, empty land and building distance, building key and empty land position should also be recorded, so she can test the API first.

Because there is no concern about timeout or space limitation, Julia likes to design a few APIs, and also learn how to write code to follow S.O.L.I.D. principles.

In C# code, function WalkFromBuildingBFS is set as public API, and also a test case is added. Make sure that BFS search algorithm is working fine.

Here is the C# practice ready for review. Here is the code review link. 

Read some posts about SOLID principles on stackoverflow.com first.

Feb. 17, 2017 10:15pm 
Read the post about SOLID principles, the link is here.

Feb. 18, 2017 11:05am 
1. Update the question of Leetcode 317 to make it more instructional - the breadth first search, including some research I did on community challenge. 

2. Study the community challenge question code review, Rainfall challenge.
     Study Java code implementation first, and then write a C# one to ask for review.


Feb. 20, 2017
Read leetcode solution discussion, one of discussion is to expedite the search, great idea I read first time:
I also tested the other three C++ solutions posted so far, they took 340-1812 ms. I think mine is faster because I don't use a fresh "visited" for each BFS. Instead, I walk only onto the cells that were reachable from all previous buildings. From the first building I only walk onto cells where grid is 0, and make them -1. From the second building I only walk onto cells where grid is -1, and I make them -2. And so on.

Celebration of 180 mark - I solved 180 Leetcode algorithms

Sept. 2, 2018

Introduction

It is so much joy for me to write easy level algorithms. I like to make it my hobby to write some algorithms and enjoy the workout time.

As a software programmer, I never know that it is so hard to build a good habit to write code every day. I like to be a competitive programmer, maybe, one of the best in the world.

180 mark 

I do not know how to approach so many Leetcode algorithms. Once my ex-coach told me to start to work on easy level algorithms, I just cannot stop. Here is one of talk we had on August 5, 2018.

Life is so good, every time I work on easy level algorithm, I know that I am preparing for more important project, and also I am training myself to be a good thinker and very good responsible person.

Whatever the company I am working for, I should be able to feel so comfortable to take the project, and focus on more customers, work with project management stuff. So excited to get 180 mark.

I wrote a blog to celebrate 150 mark on August 14, 2018, more than two weeks ago. Here is the blog.

Let us visualize the data 

Here is July 21, 2018:

Detail please refer to this blog written in July, 2018. Here is the link. 

Here is Sept. 2, 2018:

Here is my Leetcode profile.

I solved 62 easy level algorithm from July 21 to Sept 2, 2018. So much joy to work on those seventy algorithms. I never experience so much joy, once I focus on coding, I just forget everything. I know that if I am very good at doing algorithm and data structure problem solving, all I need is to be myself, and present myself very well.

Celebration of 400 algorithm solved mark

May 23, 2019

Introduction

It is time for me to celebrate 400 algorithms solved mark. I just could not believe that I was able to solve 400 algorithms.

400 mark

It is time for me to celebrate 400 mark. I like to write down some notes here as well.

I also like to document my profile, and see how good I am to involve in Leetcode community.

Things I can work on 

I need to figure out how to write post on Leetcode discuss and focus on how to create  some content based on some example, and make it very easy to follow and also demonstrate how to solve the problem by thinking about test cases. Here is the one I worked on to add some diagrams and test cases. I learned from my mock interview, the interviewee is Amazon SDE II, he came out the solution and also explained to me using those test cases.

Right now there is no upvote in my last six posts. I need to work on how to make the content more helpful.

I also need to work on contest performance. One argument is to focus on solving more algorithms and then I may be able to perform better in the contest.