Here is solution in python - https://programmingoneonone.com/hackerrank-list-comprehensions-solution-in-python.html

print([[i, j, k] for i in range(x + 1) for j in range(y + 1) for k in range(z + 1) if i + j + k != n])

result = [ [i, j, k] for i in range(x + 1) for j in range(y + 1) for k in range(z + 1) if (s := i + j + k) != n ]

cuboid = [[i,j,k] for i in range(x+1) for j in range(y+1) for k in range(z+1) if i+j+k != n]
print(cuboid)

But i dont really understand why we made range(x+1) and so on?

don't forget about itertools in python, it's tremendously powerful:

from itertools import product


if __name__ == '__main__':
    x = int(input())
    y = int(input())
    z = int(input())
    n = int(input())
    
    print(
        [
            [i, j, k] 
            for i, j, k in product(range(x + 1), range(y + 1), range(z + 1)) 
            if i + j + k != n
        ]
    )