Challenge - Roux

Define a roux array as a 1-D array such that, when it's reversed, it represents the sequence of square numbers 1, 4, 9, 16, ... with 0s interwoven between them.

# roux array of length 5
[9 0 4 0 1]

# roux array of length 8
[ 0 16  0  9  0  4  0  1]

# roux array of length 12
[ 0 36  0 25  0 16  0  9  0  4  0  1]

Implement a function called make_roux(n) that inputs n, the desired size of the array, and outputs the corresponding roux array. Then test it on the examples above.

%pip install numpy
import numpy as np

Requirement already satisfied: numpy in /home/samrat/Documents/numpy-torch-tutorials/venv/lib/python3.8/site-packages (1.24.4)
Note: you may need to restart the kernel to use updated packages.

def make_roux(n):
    res = np.zeros(n, dtype='int64')
    sequential = np.arange(start=1, stop=((n + 1)//2 + 1), dtype='int64')
    sequential_square = np.flip(sequential * sequential)
    res[(n%2 + 1)%2::2] = sequential_square
    return res

print(make_roux(5))
print(make_roux(8))
print(make_roux(12))

[9 0 4 0 1]
[ 0 16  0  9  0  4  0  1]
[ 0 36  0 25  0 16  0  9  0  4  0  1]