1.7 CTCI

gistfile1.txt

even_matrix = [
    [   0,    1,      2,     3 ],
    [   4,    5,      6,     7 ],
    [   8,    9,    10,   11 ],
    [ 12,  13,    14,  15  ]
]

odd_matrix = [
    [    0,      1,     2,     3,      4 ],
    [    5,      6,     7,     8,      9 ],
    [  10,    11,   12,   13,   14 ],
    [  15,    16,   17,   18,   19 ],
    [  20,    21,   22,   23,   24 ]
]

def _validate_input(matrix):
  size = len(matrix)
  for row in matrix:
    if len(row) != size:
      raise ValueError('Input matrix is not NxN!')

'''
Rotates an NxN matrix by 90 degrees
'''
def rotate(matrix):
  _validate_input(matrix)

  size = len(matrix)
  for row_index in range(size):
    for column_index in range(row_index):
      buffer = matrix[row_index][column_index]
      matrix[row_index][column_index] = matrix[column_index][row_index]
      matrix[column_index][row_index] = buffer

  return matrix

def print_matrix(matrix):
  for row in matrix:
    print(row)

if __name__ == '__main__':
  print_matrix(rotate(even_matrix))
  print('')
  print_matrix(rotate(odd_matrix))