Stackoverflow - code review research

Nov. 27, 2016

  Try to post the first code review on code review on stack exchange, code review section.

When I try to put the title:
Leetcode 329 Longest Increasing Path in a matrix - DFS, memorization

Here are information coming out.

  Questions that may already have your answer

3

DFS algorithm too slow 1

2

Find shortest paths in a matrix using Dijkstra's algorithm 1

1

LeetCode Minimum Path Sum algorithm 1

6

Longest Increasing Subsequence 2

6

Python implementation of the longest increasing subsequence 4

2

Picking seats in a matrix

Review the above entries.

So many to read and so good the experience is. Cannot wait to spend time on those posts. Julia knows that it is time to make changes, her research usual touched the surface only.

For example, with stackexchange code review, her research from Nov. 30 posting the question to a perfect solution (Dec. 2, 2016) on Java TreeSet class floor method and its analog in C# ends up working code - SortedSet GetViewBetween, score maximum score. It takes less than 3 days to find a practical solution, with two experts' help.

Blog reading:
Bear and steady gene - C# algorithm:
https://gist.github.com/jianminchen/153eab0defae014842e8

Woman's CodeSprint 2 - Minimum Loss - after the contest (series 2 of 10)

Nov. 20, 2016

Julia worked on the algorithm in the contest, and then solved the algorithm with full score - 35.

Here is the problem statement:

https://www.hackerrank.com/contests/womens-codesprint-2/challenges/minimum-loss

Julia's C# solution:

https://gist.github.com/jianminchen/af474846d81b96f4e70fc1a5866dca15

The ideas used in the algorithm:

Use bucket sort similar idea to go through each bucket, compare to previous if the current is less than minimum loss 

or not. Each bucket keeps the two value - max/ min value.

Study all other submissions using C++, Java, C#, JavaScript:

Actionable Items:

1. Read the code line by line, word by word; train myself to understand the code, by reading, by association 

with C#.

2. Study TreeSet - Java - class - memorize all the API, compared to C# Hashset

https://docs.oracle.com/javase/7/docs/api/java/util/TreeSet.html

My favorite Java code:
https://gist.github.com/jianminchen/3fce12eff5838fa10bff0792547d0779

A small research - TreeSet in Java is implemented as Binary search Tree?
http://stackoverflow.com/questions/4430809/making-binary-search-tree

Find the best solution written in Java:

Discussion of Time Complexity:

1. Brute force solution - O(n^2), choose any two year to compare the price. Will time-out!

2. Using Binary search - therefore, it is easy to find the minimum price, O(nlogn)
Maintain a binary search tree!

Study this C# solution using Binary search tree:

https://gist.github.com/jianminchen/c910f5d1f37309c70b489e6c75b0678c

line 16, 25 are Julia's favorite code - 

Very classical solution using binary search tree, and very clever solution.

Memorize the solution. Warm up the solution sometimes in the future.