Hi, here’s your problem today. This problem was recently asked by Microsoft:

Given a list of numbers, and a target number n, find all unique combinations of a, b, c, d, such that a + b + c + d = n.

Here’s some examples and some starting code.

def fourSum(nums, target):
  # Fill this in.

print(fourSum([1, 1, -1, 0, -2, 1, -1], 0))
# print [[-1, -1, 1, 1], [-2, 0, 1, 1]]

print(fourSum([3, 0, 1, -5, 4, 0, -1], 1))
# print [[-5, -1, 3, 4]]

print(fourSum([0, 0, 0, 0, 0], 0))
# print ([0, 0, 0, 0])