spiral_print.py

"""
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
"""


defcheck_matrix(matrix: list[list[int]]) ->bool:
# must be
matrix= [list(row) forrowinmatrix]
ifmatrixandisinstance(matrix, list):
ifisinstance(matrix[0], list):
prev_len=0
forrowinmatrix:
ifprev_len==0:
prev_len=len(row)
result=True
else:
result=prev_len==len(row)
else:
result=True
else:
result=False

returnresult


defspiral_print_clockwise(a: list[list[int]]) ->None:
"""
 >>> spiral_print_clockwise([[1, 2, 3, 4], [5, 6, 7, 8], [9, 10, 11, 12]])
 1
 2
 3
 4
 8
 12
 11
 10
 9
 5
 6
 7
 """
ifcheck_matrix(a) andlen(a) >0:
a= [list(row) forrowina]
mat_row=len(a)
ifisinstance(a[0], list):
mat_col=len(a[0])
else:
fordatina:
print(dat)
return

# horizotal printing increasing
foriinrange(mat_col):
print(a[0][i])
# vertical printing down
foriinrange(1, mat_row):
print(a[i][mat_col-1])
# horizotal printing decreasing
ifmat_row>1:
foriinrange(mat_col-2, -1, -1):
print(a[mat_row-1][i])
# vertical printing up
foriinrange(mat_row-2, 0, -1):
print(a[i][0])
remain_mat= [row[1 : mat_col-1] forrowina[1 : mat_row-1]]
iflen(remain_mat) >0:
spiral_print_clockwise(remain_mat)
else:
return
else:
print("Not a valid matrix")
return


# Other Easy to understand Approach


defspiral_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([])
 """
ifmatrix:
returnlist(matrix.pop(0)) +spiral_traversal(
 [list(row) forrowinzip(*matrix)][::-1]
 )
else:
return []


# driver code
if__name__=="__main__":
importdoctest

doctest.testmod()

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