text: #!/usr/bin/python -tt
  # Copyright 2010 Google Inc.
  # Licensed under the Apache License, Version 2.0
  # http://www.apache.org/licenses/LICENSE-2.0
  
  # Google's Python Class
  # http://code.google.com/edu/languages/google-python-class/
  
  # Additional basic list exercises
  
  
  # D. Given a list of numbers, return a list where
  # all adjacent == elements have been reduced to a single element,
  # so [1, 2, 2, 3] returns [1, 2, 3]. You may create a new list or
  # modify the passed in list.
  def remove_adjacent(nums):
      new_list = []
      cur_item = None
  
      for item in nums:
          if item == cur_item:
              # Ignores this item
              continue
          else:
              # Set the cur_item and keep it
              cur_item = item
              new_list.append(cur_item)
      return new_list
  
  
  # 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):
      list1.extend(list2)
      list1.sort()
      return list1
  
  
  # Note: the solution above is kind of cute, but unforunately list.pop(0)
  # is not constant time with the standard python list implementation, so
  # the above is not strictly linear time.
  # An alternate approach uses pop(-1) to remove the endmost elements
  # from each list, building a solution list which is backwards.
  # Then use reversed() to put the result back in the correct order. That
  # solution works in linear time, but is more ugly.
  
  
  # Simple provided test() function used in main() to print
  # what each function returns vs. what it's supposed to return.
  def test(got, expected):
      if got == expected:
          prefix = ' OK '
      else:
          prefix = '  X '
      print('%s got: %s expected: %s' % (prefix, repr(got), repr(expected)))
  
  
  # Calls the above functions with interesting inputs.
  def main():
      print('remove_adjacent')
      test(remove_adjacent([1, 2, 2, 3]), [1, 2, 3])
      test(remove_adjacent([2, 2, 3, 3, 3]), [2, 3])
      test(remove_adjacent([]), [])
  
      print()
      print('linear_merge')
      test(linear_merge(['aa', 'xx', 'zz'], ['bb', 'cc']),
           ['aa', 'bb', 'cc', 'xx', 'zz'])
      test(linear_merge(['aa', 'xx'], ['bb', 'cc', 'zz']),
           ['aa', 'bb', 'cc', 'xx', 'zz'])
      test(linear_merge(['aa', 'aa'], ['aa', 'bb', 'bb']),
           ['aa', 'aa', 'aa', 'bb', 'bb'])
  
  
  if __name__ == '__main__':
      main()
  