title: How can I merge two lists and sort them working in 'linear' time?
body: <p>I have this, and it works:</p>
  
  <pre><code># E. Given two lists sorted in increasing order, create and return a merged
  # list of all the elements in sorted order. You may modify the passed in lists.
  # Ideally, the solution should work in "linear" time, making a single
  # pass of both lists.
  def linear_merge(list1, list2):
    finalList = []
    for item in list1:
      finalList.append(item)
    for item in list2:
      finalList.append(item)
    finalList.sort()
    return finalList
    # +++your code here+++
    return
  </code></pre>
  
  <p>But, I'd really like to learn this stuff well. :) What does 'linear' time mean?</p>