Spiral Matrix: two separate algorithm challenge questions
Goals

If given an integer N, return an n x n Matrix in a matrix spiral.

Given an m x n matrix, return all elements in a spiral (clockwise order)
(Spoiler Alert: Below the fold, you’ll find the solutions so if you haven’t already tried them yourself then don’t scroll down. If you don’t mind seeing the approach and gaining some insight before you try or if you have already solved it, scroll on 🤘🏽)
The above items are actually two separate challenge questions. The algorithm for each is almost exactly the same, with a few minor modifications. I started working on item number 1 and initially, I made some good progress but after a few days of scratching my head, I decided it would be wiser to get some assistance and after some research realized a few important things.
Thoroughly whiteboarding the steps (on paper or on an actual whiteboard) toward a solution before coding is immensely valuable. If you can completely pseudocode it, you’re golden.
Breaking the problem into smaller subproblems will help a lot.
I am a visual learner, so when I try to build a theoretical model of the solution, I have a better understanding of where I’m going.
Challenge 1
Create a function that takes an integer N and returns a NxN Matrix Spiral
I did subdivide the problem into smaller ones and was able to pass the initial test cases but eventually, the test cases got too big to solve, which is where I hit a wall.
One of the mistakes I made when starting my initial solution was to glaze over a matrix representation of the final solution. Inspecting a drawing of one more thoroughly would have given me more clues as to the pivotal pieces of this algorithm—counters.
Once you set up all your variables to represent all the four corners of the matrix or each start row, start column, end column, and end row, one while loop and four separate for loops within it are all that is needed.
n x n Matrix
The Psuedocode that helped me get my head around the challenge, courtesy of John Peña

Create an empty array of arrays called ‘results’

Create a counter variable, starting at 1

As long as (start column <= end column) AND (start row <= end row)

Loop from start column to end column
 At results[start_row][i] assign counter variable
 Increment counter
 Increment start row
 Loop from start row to end row
 At results[i][end_column] assign counter variable
 Increment counter
 Decrement end row
 …repeat for the other two sides

Once that is set up, insert a while loop as long as the conditions previously mentioned are met in the pseudocode above (3rd bullet point) and start iterating the top row from left to right, assigning values per column as you move right.
 The complete code can be found on a Replit
(Replit is currently having issues with Hacker and Teams so if you don’t see code right away, please check back or build out the above algorithm in your own IDE to test it and have fun).
Challenge 2
Given an m x n matrix, return all elements in a spiral (clockwise order)
The only difference between this challenge and the first one is the parameter requirement.
Challenge 1 asks us to return a spiral matrix when given an integer N and challenge 2 asks us to return a spiral matrix when given an m x n matrix, so the parameter will be a 2dimensional array, which you’ll need to iterate through and output a spiral matrix for.
 The algorithm for this challenge is basically identical save for very minor differences.
 See the Replit solution and compare
(Replit is currently having issues with Hacker and Teams so if you don’t see code right away, please check back or build out the above algorithm in your own IDE to test it and have fun).