Cant get my head round the algorithm

[Yoriz]

List 500 700 1000 1400 2000
target 2300

There inst a direct match but the closest is 1400 + 700 which gives me 2100. And this the right answer.

The closet is 1000 + 1400 which gives 2400

items = (500, 700, 1000, 1400, 2000)
target = 2300

from itertools import combinations

nearest = target
best_match = None

for item1, item2 in combinations(items, 2):
    differance = abs(target - (item1 + item2))
    if differance <= nearest:
        best_match = (item1, item2)
        nearest = differance
        
print(f'The best match to {target} is {best_match} at {sum(best_match)}')

Output:
The best match to 2300 is (1000, 1400) at 2400

Unless the best match must be must be equal to or below the target.

items = (500, 700, 1000, 1400, 2000)
target = 2300

from itertools import combinations

nearest = target
best_match = None

for item1, item2 in combinations(items, 2):
    differance = abs(target - (item1 + item2))
    if differance <= nearest and (item1 + item2) <= target:
        best_match = (item1, item2)
        nearest = differance
        
print(f'The best match to {target} is {best_match} at {sum(best_match)}')

Output:
The best match to 2300 is (700, 1400) at 2100