Python: Check the sum of three elements from three arrays is equal to a target value

Last update on April 17 2025 13:06:03 (UTC/GMT +8 hours)

Three Array Sum Combinations

Write a Python program to check the sum of three elements (each from an array) from three arrays is equal to a target value. Print all those three-element combinations.

Sample data:
/*
X = [10, 20, 20, 20]
Y = [10, 20, 30, 40]
Z = [10, 30, 40, 20]
target = 70
*/

Sample Solution:

Python Code:

# Import the 'itertools' module for advanced iteration tools and 'partial' from 'functools'.
import itertools
from functools import partial

# Define three lists and a target sum value.
X = [10, 20, 20, 20]
Y = [10, 20, 30, 40]
Z = [10, 30, 40, 20]
T = 70

# Define a function to check if the sum of a set of numbers equals a given target.
def check_sum_array(N, *nums):
    if sum(x for x in nums) == N:
        return (True, nums)
    else:
        return (False, nums)

# Generate the Cartesian product of the three lists.
pro = itertools.product(X, Y, Z)

# Create a partial function using the 'check_sum_array' function and the target sum 'T'.
func = partial(check_sum_array, T)

# Use 'starmap' to apply the partial function to each element in the Cartesian product.
sums = list(itertools.starmap(func, pro))

# Use a set to store unique valid combinations.
result = set()

# Iterate through the sums and print unique valid combinations.
for s in sums:
    if s[0] == True and s[1] not in result:
        result.add(s[1])
        print(result)

Sample Output:

{(10, 20, 40)}
{(10, 20, 40), (10, 30, 30)}
{(10, 20, 40), (10, 30, 30), (10, 40, 20)}
{(10, 20, 40), (10, 30, 30), (20, 10, 40), (10, 40, 20)}
{(10, 20, 40), (20, 20, 30), (10, 30, 30), (20, 10, 40), (10, 40, 20)}
{(10, 20, 40), (10, 40, 20), (20, 10, 40), (10, 30, 30), (20, 20, 30), (20, 30, 20)}
{(10, 20, 40), (10, 40, 20), (20, 10, 40), (20, 40, 10), (10, 30, 30), (20, 20, 30), (20, 30, 20)}

Explanation:

The above Python code tries to find unique combinations of elements from three lists (X, Y, Z) whose sum is equal to a target value T. Here's a brief explanation:

Import the "itertools" module for advanced iteration and the "partial()" function from the "functools" module.
Define three lists (X, Y, Z) and a target sum value (T).
Define a function (check_sum_array) that checks if the sum of a set of numbers equals a given target.
Generate the Cartesian product of the three lists (X, Y, Z).
Create a partial function using the "check_sum_array()" function and the target sum T.
Apply the partial function to each element in the Cartesian product using "starmap".
Use a set (result) to store unique valid combinations.
Iterate through the sums and print unique valid combinations.

Flowchart:

For more Practice: Solve these Related Problems:

Write a Python program to find all combinations of one element from each of three arrays whose product equals a target value.
Write a Python program to determine the combination of elements from three arrays whose sum is closest to a given target.
Write a Python program to count the number of combinations of elements from three arrays that exactly sum to a target value.
Write a Python program to print all unique three-element combinations (one from each array) that add up to a specific target.

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