Python program to return True if sum of any 3 numbers in array is equal to key else return false

random_3_number_array_sum_equal_key.py

# -*- coding: utf-8 -*-
"""
Created on Sat May  9 23:28:42 2020

@author: bineet

"""

# given an array and if sum of any 3 numbers in array is equal to key 
# then return true else false
arr = [-1, 0, 2, 4, 5, 3]
key = 3

def check_sum(arr):
    for i in range(0, len(arr)):
        for j in range(i+1, len(arr)):
            for k in range(j+1, len(arr)):
                if arr[i] + arr[j] + arr[k] == key:
                    return True
    return False

# test cases
assert check_sum([-1, 0, 2, 4, 5, 3]) == True
assert check_sum([-1, 0, 2, -4, 5, 3]) == True
assert check_sum([-1, 0, 2, 41, 51, 3]) == False