title: Create a sum of 1000, 2000, etc. from set of numers
body: <p>Ok, so here's the problem:</p>
  
  <p>I need to find any number of intem groups from 50-100 item set that add up to 1000, 2000, ..., 10000.</p>
  
  <p>Input: list of integers</p>
  
  <p>Integer can be on one list only.</p>
  
  <p>Any ideas on algorithm?</p>