Algorithm to determine which numbers in a list are the sum of a given number -

i have coding question try solve. haven't been able come algorithm yet.

given number x (e.g. 200), determine numbers list (e.g.: 4,5,10, 10, 23,67,889, 150, 50) when summed equal x. in case answer (50, 150). far thought first sorting the list (lowest highest) loop through adding numbers until value greater x. discard remaining numbers in list since not needed (e.g. 889). have list of numbers required produce sum of 200. need determine numbers sum 200.

currently stuck @ point.

any thoughts appreciated.

this knapsack problem. refer here https://en.m.wikipedia.org/wiki/knapsack_problem