Rotate Image

Question

Given an n x n 2D matrix representing an image, rotate the image by 90 degrees (clockwise).

Example 1

Input: [[1,2,3],
        [4,5,6],
        [7,8,9]]

Output: [[7,4,1],
         [8,5,2],
         [9,6,3]]

Solution

▭

all//Rotate Image.py

def rotateImage(a):
    N = len(a[0])
    for i in range(N // 2):
        for j in range(i, N - i - 1):
            temp = a[i][j]
            a[i][j] = a[N - 1 - j][i]
            a[N - 1 - j][i] = a[N - 1 - i][N - 1 - j]
            a[N - 1 - i][N - 1 - j] = a[j][N - 1 - i]
            a[j][N - 1 - i] = temp
    return a

▯

all//Rotate Image.py

def rotateImage(a):
    N = len(a[0])
    for i in range(N // 2):
        for j in range(i, N - i - 1):
            temp = a[i][j]
            a[i][j] = a[N - 1 - j][i]
            a[N - 1 - j][i] = a[N - 1 - i][N - 1 - j]
            a[N - 1 - i][N - 1 - j] = a[j][N - 1 - i]
            a[j][N - 1 - i] = temp
    return a