title: Compare 2 lists to find an equal or approximate match without doing N^2 iteration
body: <p>I have two lists:</p>
  
  <pre><code>list1 = [101, 110, 136]
  list2 = [101.04, 264.5, 379.9, 466.4, 629.6, 724.4, 799.8, 914.3]
  </code></pre>
  
  <p>Iterate over <code>list1</code> and compare each element in this list with the elements in <code>list2</code>. If there is a number encountered in the 2nd list which is an exact match or an approximate match to the element in <code>list1</code> then output that match.</p>
  
  <p>Note: I want to avoid the N^2 iteration strictly as I want to do it as efficiently as possible</p>