Answer to Question #182448 in Python for adhi chinna

Question

Rotate Matrix Rings

Given matrix of order M*N and a value K, write a program to rotate each ring of the matrix clockwise by K elements. If in any ring has less than or equal to K elements, then don’t rotate that ring.Input

first line of input will be two space-separated integers, denoting the M and N.

next M lines will contain N space-separated integers.

next line will contain an integer, denoting K.Output

output should be M*N matrix by rotating the matrix by K element.Explanation

if the given M and N are 4 and 4 respectively. If the matrix elements

1 2 3 4

5 6 7 8

9 10 11 12

13 14 15 16

If the given K is 3. Rotate each ring of the matrix by 3 elements.

In the above matrix, the elements (1, 2, 3, 4, 8, 12, 16, 15, 14, 13, 9, 5) is a ring, similarly, the elements (6, 7, 11, 10) will make a ring.

Therefore, by rotating each ring in clockwise direction by 3 elements will give (13, 9, 5, 1, 2, 3, 4, 8, 12, 16, 15, 14) and (10, 6, 7, 11). So the output should be

13 9 5 1

14 7 11 2

15 6 10 3

16 12 8 4

Answer 1

def print_matr():
    global matr
    for row in matr:
        for el in row:
            print(str(el) + " ", end='')
        print()
    print()
        
def rings_amount():
    global rows, cols, k
    for ring_num in range(min(rows,cols)//2):
        if 2 * (rows + cols - 4 * ring_num) - 4 < k:
            print('break')
            return ring_num
    else:
        return ring_num + 1

def rotate_by_one(ring_num):
    global matr, rows, cols
    left = top = ring_num
    right = cols - 1 - ring_num
    bottom = rows - 1 - ring_num
    temp = matr[ring_num][ring_num]
    
    # left column
    for row_pos in range(top,bottom):
        matr[row_pos][left] = matr[row_pos+1][left]
    #print_matr()
    
    # bottom row
    for col_pos in range(left,right):
        matr[bottom][col_pos] = matr[bottom][col_pos+1]
    #print_matr()
    
    # right column
    for row_pos in range(bottom,top,-1):
        matr[row_pos][right] = matr[row_pos-1][right]
    #print_matr()
    
    # top row
    for col_pos in range(right,left,-1):
        matr[top][col_pos] = matr[top][col_pos-1]
    matr[ring_num][ring_num+1] = temp
    #print_matr()

rows = m = 4
cols = n = 4
k = 3

matr = [
    [1, 2, 3, 4],
    [5, 6, 7, 8],
    [9, 10, 11, 12],
    [13, 14, 15, 16]
]

res = [
    [13, 9, 5, 1],
    [14, 7, 11, 2],
    [15, 6, 10, 3],
    [16, 12, 8, 4]
]

ring_nums = rings_amount()

for _ in range(k):
    for ring_num in range(ring_nums):
        rotate_by_one(ring_num)

print_matr()