CodeSignal - rotateImage.py

CodeSignal-RotateImage.txt

Note: Try to solve this task in-place (with O(1) additional memory), since this is what you'll be asked to do during an interview.

You are given an n x n 2D matrix that represents an image. Rotate the image by 90 degrees (clockwise).

Example

For

a = [[1, 2, 3],
     [4, 5, 6],
     [7, 8, 9]]
the output should be

solution(a) =
    [[7, 4, 1],
     [8, 5, 2],
     [9, 6, 3]]
Input/Output

[execution time limit] 4 seconds (py3)

[input] array.array.integer a

Guaranteed constraints:
1 ≤ a.length ≤ 100,
a[i].length = a.length,
1 ≤ a[i][j] ≤ 104.

[output] array.array.integer

[Python 3] Syntax Tips

# Prints help message to the console
# Returns a string
def helloWorld(name):
    print("This prints to the console when you Run Tests")
    return "Hello, " + name

def solution(a):
    row_len = len(a)
    col_len = len(a[0])
    
    new_matrix = []
    for ri in range(row_len):
        new_row = []
        for ci in range(col_len):
            new_row.insert(0, a[ci][ri])
        
        new_matrix.append(new_row)
        
    return new_matrix

def solution(a):
a.reverse()
for i in range(len(a)):
for j in range(i):
a[i][j], a[j][i] = a[j][i],a[i][j]
return a