clockwise rotate 2d matrix

matrix_rotate_clockwise.py

class Solution:
    def rotate(self, matrix):
        '''
        :type matrix: list of list of int
        :rtype: list of list of int
        '''
        # assuming nxm
        ROWS = len(matrix)
        COLS = len(matrix[0])
        row = ROWS - 1
        # initialize empty matrix
        new_matrix = [[0 for _ in range(COLS)] for _ in range(ROWS)]
        # do operation
        for new_col in range(COLS):
            for new_row in range(ROWS):
                # col is new_r since row = col index sqr matrix 
                new_matrix[new_row][new_col] = matrix[row][new_row]
            row -= 1
        return new_matrix



class Solution:
    def rotate(self, matrix):
        '''
        :type matrix: list of list of int
        :rtype: list of list of int
        '''
        # size = len(matrix) - 1
        # layers = len(matrix)//2

        # Optimized: still same complexity but with in-place swaps.
        
        size = len(matrix) - 1
        layers = len(matrix) // 2

        for layer in range(0, layers):
            right_layer_limit = size - layer
            for row in range(layer, right_layer_limit):
                top = matrix[layer][row]
                right = matrix[row][right_layer_limit]
                bottom = matrix[right_layer_limit][size-row]
                left = matrix[size-row][layer]
                
                matrix[layer][row] = left
                matrix[row][right_layer_limit] = top
                matrix[right_layer_limit][size - row] = right
                matrix[size - row][layer] = bottom

        return matrix