48. Rotate Image.py

class Solution:
    def rotate(self, matrix: List[List[int]]) -> None:
        """
        Do not return anything, modify matrix in-place instead.
        """
        m = len(matrix)
        n = len(matrix[0])
        row_b = 0 # 0-> 1
        row_e = m-1 # 2->1
        col_b = 0
        col_e = n-1
        if n == 1:
            return 
        while row_b <= row_e and col_b <= col_e:
            
            for i in range(n-1):
                tmp = matrix[row_b][col_b+i]
                matrix[row_b][col_b+i] =  matrix[row_e-i][col_b]
                matrix[row_e-i][col_b] = matrix[row_e][col_e-i]
                matrix[row_e][col_e-i] = matrix[row_b+i][col_e]
                matrix[row_b+i][col_e] = tmp
            
            row_b+=1
            row_e-=1
            col_b+=1
            col_e-=1
            n -= 2
            
    def rotate(self, matrix: List[List[int]]) -> None:
        def transpose(mat):
            n = len(mat)
            for i in range(n):
                for j in range(i, n):
                    mat[i][j], mat[j][i] = mat[j][i], mat[i][j]
        def reverse(nums):
            l = 0
            r = len(nums)-1
            while l < r:
                nums[l], nums[r] = nums[r], nums[l]
                l+=1
                r-=1
        n = len(matrix)
        if n == 1:
            return 
        transpose(matrix)
        for i in range(n):
            reverse(matrix[i])