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I found this interview question online at Pramp:

Given a 2D array (matrix) inputMatrix of integers, create a function spiralCopy that copies inputMatrix’s values into a 1D array in a spiral order, clockwise. Your function then should return that array. Analyze the time and space complexities of your solution.

Example:

input: inputMatrix = [ [1, 2, 3, 4, 5], [6, 7, 8, 9, 10], [11, 12, 13, 14, 15], [16, 17, 18, 19, 20] ]

output: [1, 2, 3, 4, 5, 10, 15, 20, 19, 18, 17, 16, 11, 6, 7, 8, 9, 14, 13, 12] 

See the illustration below to understand better what a clockwise spiral order looks like. Clockwise spiral order

[input] array.array.integer inputMatrix

$1 ≤ inputMatrix[0].length ≤ 100 1 ≤ inputMatrix.length ≤ 100 $

[output] array.integer

My solution

def spiral_copy(inputMatrix):
 output = 

 top_row = 0
 bottom_row = len(inputMatrix) - 1
 left_col = 0
 right_col = len(inputMatrix[0]) - 1

 while top_row <= bottom_row and left_col <= right_col:

 for i in range(left_col, right_col + 1):
 output.append(inputMatrix[top_row][i])
 top_row += 1

 for i in range(top_row, bottom_row + 1):
 output.append(inputMatrix[i][right_col])
 right_col -= 1

 if top_row > bottom_row: break

 for i in range(right_col, left_col - 1, -1):
 output.append(inputMatrix[bottom_row][i])
 bottom_row -= 1 

 if left_col > right_col: break

 for i in range(bottom_row, top_row - 1, -1):
 output.append(inputMatrix[i][left_col])
 left_col += 1 

 return output

Input 
[[1,2],[3,4]]
Expected Result
[1, 2, 4, 3]
Input
[[1,2],[3,4]
Expected Result
[1, 2, 4, 3]

Input
[[1,2,3,4],[5,6,7,8],[9,10,11,12]]
Expected Result
[1, 2, 3, 4, 8, 12, 11, 10, 9, 5, 6, 7]

input
[[1,2],[3,4]
Expected Result
[1, 2, 3, 4, 5, 6, 12, 18, 17, 16, 15, 14, 13, 7, 8, 9, 10, 11]

Input
[[1,0],[0,1]]
Expected Result
[1, 0, 1, 0]

Input
[[1,2,3],[4,5,6],[7,8,9]]
Expected Result
[1, 2, 3, 6, 9, 8, 7, 4, 5]