Answer to Question #167590 in Python for Sri

Question

Given an MxN matrix, write a program to print all Anti-Diagonals elements of the matrix

Input:

The first line of input will contain M, N values separated by space.

The second line will contain matrix A of dimensions MxN.

Output:

The output should contain anti-diagonal elements separated by a line.

Sample Input 1:

2 3

1 5 5

2 7 8

Output:

1
5 2
5 7
8

Sample Input 2:

3 4

1 2 3 4

5 6 7 8

9 10 11 12

Output:

1
2 5
3 6 9
4 7 10
8 11
12

Answer 1

def antidiag(matrix):
    """Prints anti-diagonals of matrix. One per line.
    
    >>> antidiag([
    ... [1, 5, 5],
    ... [2, 7, 8]
    ... ])
    1
    5 2
    5 7
    8
    >>> antidiag([
    ... [1, 2, 3, 4],
    ... [5, 6, 7, 8],
    ... [9, 10, 11, 12]
    ... ])
    1
    2 5
    3 6 9
    4 7 10
    8 11
    12
    >>> antidiag([
    ... [1, 2],
    ... [3, 4],
    ... [5, 6],
    ... [7, 8]
    ... ])
    1
    2 3
    4 5
    6 7
    8
    >>> antidiag([
    ... [1, 2, 3],
    ... [4, 5, 6],
    ... [7, 8, 9],
    ... [10, 11, 12]
    ... ])
    1
    2 4
    3 5 7
    6 8 10
    9 11
    12
    """
    M = len(matrix)
    N = len(matrix[0])
    result = [[] for _ in range(M+N -1)]
    for i in range(M):
        for j in range(N):
            result[i+j].append(matrix[i][j])
    for d in result:
        print(*d)

# Program
M, N = list(int(x) for x in input('M N: ').split())
A = []
for i in range(M):
    A.append([int(x) for x in input('A[%d]: ' % (i+1)).split()])
antidiag(A)

if __name__ == '__main__':
    import doctest
    doctest.testmod()