Complete the Square (Matrix)

Sadly, the mathematical world is biased in favor of square matrices. As such, this challenge will help rectangular matrices by making them square.

For example, for the matrix:

[
  [1, 2],
  [3, 4],
  [5, 6]
]

This can be done by padding it with a column of zeroes on the right to get:

[
  [1, 2, 0],
  [3, 4, 0],
  [5, 6, 0]
]

While for the matrix:

[
  [1, 2, 3, 4],
  [5, 6, 7, 8]
]

One can pad it with two rows of zeros at the bottom to get:

[
  [1, 2, 3, 4],
  [5, 6, 7, 8],
  [0, 0, 0, 0],
  [0, 0, 0, 0]
]

Write a function that pads a rectangular matrix with zeros on the right or at the bottom to make it square.

Examples

complete_square([
  [2, 5]
]) ➞ [
  [2, 5],
  [0, 0]
]

complete_square([
  [2, 5],
  [1, 7]
]) ➞ [
  [2, 5],
  [1, 7]
]

complete_square([
  [1, 2],
  [3, 4],
  [5, 6]
 ]) ➞ [
  [1, 2, 0],
  [3, 4, 0],
  [5, 6, 0]
]

Notes

• Matrices should be padded on the right or at the bottom, but not both simultaneously (i.e. the size of the biggest direction shouldn't change).
• If the input is already a square matrix, just return that matrix.