Matrix Rotation - Code Review - Series 3 of 10+

Dec. 6, 2016
Problem statement:
https://www.hackerrank.com/challenges/matrix-rotation-algo

Study code:
https://gist.github.com/jianminchen/1c1c07b5454a43d493264c6db4444ea3

Because there are over hundred C# solution to review, Julia likes to go over them first, mark good solutions to study first.

1. jaygundy
https://www.hackerrank.com/rest/contests/master/challenges/matrix-rotation-algo/hackers/jaygundy/download_solution

2. pableFomenta - similar to code review #2
https://www.hackerrank.com/rest/contests/master/challenges/matrix-rotation-algo/hackers/PabloFomenta/download_solution

Ideas to study code submissions:
1. Study all submissions using JavaScript with full score.
  30+ solutions

2. Study submissions - using filters:

Carnegie Mellon University, Pittsburgh(30+)
MIT ()
Stanford University
University of California, Berkeley

Amazon (20+)
Google  (20+)
Facebook (5)
     Facebook - Player-1

Look for code with good style and design ideas:

Facebook:
1. Java
Define Set function, line 65 - 69.
https://gist.github.com/jianminchen/5e7796bce5a9420472bec31a2cc6e30b

Google

2. C++
line 25, int lt_corner - variable is very clear and meaningful
https://gist.github.com/jianminchen/d8843e292df6e9070e5f55c907ad0f69

3. C++
Matrix at most 300x300, so total size at most is 300*300*4bytes = 360MB, 360KB, HackerRank maximum space is 512MB.
line 8: int M[300][300]
Declare a global variable - jagged array, the code is very easy to read.
Use the condition:  n <= 300
https://gist.github.com/jianminchen/15ff14b51ab1c9f86084dbba4a036684

4. C

For any element in the array, use one for loop to rotate k steps. Very smart handling - code from
line 29 - 45, total 16 lines of code
https://gist.github.com/jianminchen/137807675ba27fd532ffaed4f98a68df

5. Java
Cannot believe!
https://gist.github.com/jianminchen/6e84dfcf2fb222d84900bda27687e6a1

Amazon

Java
6. Design a class: LinkedListLight, with an API  - RotateBy(int steps)
https://gist.github.com/jianminchen/b7cb950b70563b56cb37909e72e0b48c

Standford:

JavaScript
7. https://gist.github.com/jianminchen/ae14bc0d764240d03831e6429337199a