Python Program to Print matrix in snake pattern

Given an n x n matrix .In the given matrix, you have to print the elements of the matrix in the snake pattern.

Examples:

Input :mat[][] = { {10, 20, 30, 40},
                   {15, 25, 35, 45},
                   {27, 29, 37, 48},
                   {32, 33, 39, 50}};
              
Output : 10 20 30 40 45 35 25 15 27 29
         37 48 50 39 33 32 

Input :mat[][] = { {1, 2, 3},
                   {4, 5, 6},
                   {7, 8, 9}};
Output : 1 2 3 6 5 4 7 8 9

Python Program to Print matrix in snake pattern

We traverse all rows. For every row, we check if it is even or odd. If even, we print from left to right else print from right to left. 

Python3

# Python 3 program to print
# matrix in snake order
M = 4
N = 4


def printf(mat):
    global M, N

    # Traverse through all rows
    for i in range(M):

        # If current row is
        # even, print from
        # left to right
        if i % 2 == 0:
            for j in range(N):
                print(str(mat[i][j]),
                      end=" ")

        # If current row is
        # odd, print from
        # right to left
        else:
            for j in range(N - 1, -1, -1):
                print(str(mat[i][j]),
                      end=" ")


# Driver code
mat = [[10, 20, 30, 40],
       [15, 25, 35, 45],
       [27, 29, 37, 48],
       [32, 33, 39, 50]]

printf(mat)

# This code is contributed
# by ChitraNayal

Output

10 20 30 40 45 35 25 15 27 29 37 48 50 39 33 32 

Time complexity: O(n^m) ,Traversing over all the elements of the matrix, therefore N X M elements are there.
Auxiliary space : O(1)

Reversing Alternate rows Using Slicing

Python3

# Python 3 program to print
# matrix in snake order
M = 4
N = 4


def printf(mat):
    global M, N
    # Traverse through all rows
    for i in range(M):
        if i % 2 != 0:
            mat[i] = mat[i][::-1]
    for i in range(M):
        for j in range(N):
            print(mat[i][j], end=' ')


# Driver code
mat = [[10, 20, 30, 40],
       [15, 25, 35, 45],
       [27, 29, 37, 48],
       [32, 33, 39, 50]]

printf(mat)

# This code is contributed
# by vikkycirus

Output

10 20 30 40 45 35 25 15 27 29 37 48 50 39 33 32 

Time Complexity: O(N x M), Traversing over all the elements of the matrix, therefore N X M elements are there.
Auxiliary Space: O(1)

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