Answer to Question #211579 in Python for sudheer

Question

Given a 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.

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

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

# Function to rotate a matrix
def rotateMatrix(mat):
 
    if not len(mat):
        return
     
 
    top = 0
    bottom = len(mat)-1
 
    left = 0
    right = len(mat[0])-1
 
    while left < right and top < bottom:
        # current row
        prev = mat[top+1][left]
 
        # Move elements of top row one step right
        for i in range(left, right+1):
            curr = mat[top][i]
            mat[top][i] = prev
            prev = curr
 
        top += 1
 
        # Move elements of rightmost column one step downwards
        for i in range(top, bottom+1):
            curr = mat[i][right]
            mat[i][right] = prev
            prev = curr
 
        right -= 1
 
        # Move elements of bottom row one step left
        for i in range(right, left-1, -1):
            curr = mat[bottom][i]
            mat[bottom][i] = prev
            prev = curr
 
        bottom -= 1
 
        # Move elements of leftmost column one step upwards
        for i in range(bottom, top-1, -1):
            curr = mat[i][left]
            mat[i][left] = prev
            prev = curr
 
        left += 1
 
    return mat
 
# Function to print matrix
def printMatrix(mat):
    for row in mat:
        print (row)



#matrix
M, N = input().split()


M, N = int(M), int(N)


matrix = []


for _ in range(M):


    row = [int(x) for x in input().split()]


    matrix.append(row)


K = int(input())


for i in range(K):
    mat = rotateMatrix(matrix)


printMatrix(mat)