48_Rotate_Image.py

 # Brute Force

class Solution:
    def rotate(self, matrix: List[List[int]]) -> None:
        n = len(matrix)
        rotated = [[0] * n for _ in range(n)]
        
        for i in range(n):
            for j in range(n):
                rotated[j][n - 1 - i] = matrix[i][j]
        
        for i in range(n):
            for j in range(n):
                matrix[i][j] = rotated[i][j]


# 2nd way
# 2. Rotate By Four Cells
class Solution:
    def rotate(self, matrix: List[List[int]]) -> None:
        l, r = 0, len(matrix) - 1
        while l < r:
            for i in range(r - l):
                top, bottom = l, r

                # save the topleft
                topLeft = matrix[top][l + i]

                # move bottom left into top left
                matrix[top][l + i] = matrix[bottom - i][l]

                # move bottom right into bottom left
                matrix[bottom - i][l] = matrix[bottom][r - i]

                # move top right into bottom right
                matrix[bottom][r - i] = matrix[top + i][r]

                # move top left into top right
                matrix[top + i][r] = topLeft
            r -= 1
            l += 1




# 3. Reverse And Transpose
# Time complexity: O(n 2)
# Space complexity: O(1)
class Solution:
    def rotate(self, matrix: List[List[int]]) -> None:
        # Reverse the matrix vertically
        matrix.reverse()

        # Transpose the matrix
        for i in range(len(matrix)):
            for j in range(i + 1, len(matrix)):
                matrix[i][j], matrix[j][i] = matrix[j][i], matrix[i][j]