This gist solves the problem of determining whether if given array can be divided into three non empty partitions and sum of those partitions is same.

tell_if_array_can_be_divided_into_three_equal_sums.py

def check_if_passes(input_array):
    is_divisible = sum(input_array) % 3 == 0
    if not is_divisible:
        return is_divisible
    chunk = sum(input_array) / 3
    entries = []
    addition = 0
    for item in input_array:
        addition = item + addition
        if addition == chunk:
            entries.append(addition)
            addition = 0
    return len(entries) == 3


my_array = [3, 3, 6, 5, -2, 2, 5, 1, -9, 4]

print("\nThe result is: {0}".format(check_if_passes(my_array)))

leetcode source: https://leetcode.com/problems/partition-array-into-three-parts-with-equal-sum/