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"""

This program print the matrix in spiral form.

This problem has been solved through recursive way.

Matrix must satisfy below conditions

i) matrix should be only one or two dimensional

ii) number of column of all rows should be equal

"""

def check_matrix(matrix: list[list[int]]) -> bool:

# must be

matrix = [list(row) for row in matrix]

if matrix and isinstance(matrix, list):

if isinstance(matrix[0], list):

prev_len = 0

for row in matrix:

if prev_len == 0:

prev_len = len(row)

result = True

else:

result = prev_len == len(row)

else:

result = True

else:

result = False

return result

def spiral_print_clockwise(a: list[list[int]]) -> None:

"""

>>> spiral_print_clockwise([[1, 2, 3, 4], [5, 6, 7, 8], [9, 10, 11, 12]])

"""

if check_matrix(a) and len(a) > 0:

a = [list(row) for row in a]

mat_row = len(a)

if isinstance(a[0], list):

mat_col = len(a[0])

else:

for dat in a:

print(dat)

return

# horizotal printing increasing

for i in range(0, mat_col):

print(a[0][i])

# vertical printing down

for i in range(1, mat_row):

print(a[i][mat_col - 1])

# horizotal printing decreasing

if mat_row > 1:

for i in range(mat_col - 2, -1, -1):

print(a[mat_row - 1][i])

# vertical printing up

for i in range(mat_row - 2, 0, -1):

print(a[i][0])

remain_mat = [row[1 : mat_col - 1] for row in a[1 : mat_row - 1]]

if len(remain_mat) > 0:

spiral_print_clockwise(remain_mat)

else:

return

else:

print("Not a valid matrix")

return

# Other Easy to understand Approach

def spiral_traversal(matrix: list[list]) -> list[int]:

"""

>>> spiral_traversal([[1, 2, 3, 4], [5, 6, 7, 8], [9, 10, 11, 12]])

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

Example:

matrix = [[1, 2, 3, 4], [5, 6, 7, 8], [9, 10, 11, 12]]

Algorithm:

Step 1. first pop the 0 index list. (which is [1,2,3,4] and concatenate the

output of [step 2])

Step 2. Now perform matrix’s Transpose operation (Change rows to column

and vice versa) and reverse the resultant matrix.

Step 3. Pass the output of [2nd step], to same recursive function till

base case hits.

Dry Run:

Stage 1.

[1, 2, 3, 4] + spiral_traversal([

[8, 12], [7, 11], [6, 10], [5, 9]]

])

Stage 2.

[1, 2, 3, 4, 8, 12] + spiral_traversal([

[11, 10, 9], [7, 6, 5]

])

Stage 3.

[1, 2, 3, 4, 8, 12, 11, 10, 9] + spiral_traversal([

[5], [6], [7]

])

Stage 4.

[1, 2, 3, 4, 8, 12, 11, 10, 9, 5] + spiral_traversal([

[5], [6], [7]

])

Stage 5.

[1, 2, 3, 4, 8, 12, 11, 10, 9, 5] + spiral_traversal([[6, 7]])

Stage 6.

[1, 2, 3, 4, 8, 12, 11, 10, 9, 5, 6, 7] + spiral_traversal([])

"""

if matrix:

return list(matrix.pop(0)) + spiral_traversal(list(zip(*matrix))[::-1])

else:

return []

# driver code

if __name__ == "__main__":

import doctest

doctest.testmod()

a = [[1, 2, 3, 4], [5, 6, 7, 8], [9, 10, 11, 12]]

spiral_print_clockwise(a)