title: Generate ordered list of sum between elements in large lists
body: <p>I'm not sure whether this question should be posted in math of overflow, but here we go.</p>
  
  <p>I have an arbitrary amount of ordered lists (say 3 for example) with numerical values. These lists can be long enough that trying all combinations of values becomes too computationally heavy.</p>
  
  <p>What I need is to get an ordered list of possible sums when picking one value from each of the lists. Since the lists can be large, I only want the N smallest sums.</p>
  
  <p>What I've considered is to step down one of the lists for each iteration. This however misses many cases that would have been possible if another list would have been chosen for that step.</p>
  
  <p>An alternative would be a recursive solution, but that would generate many duplicate cases instead. </p>
  
  <p>Is there any known methods that could solve such a problem?</p>