new_contents: """Recursive Staircase.
  
  How many paths up a stair of say 100 steps if the child jumps 1, 2 or 3 steps?
  
  F(n) = F(n - 1) + F(n - 2) + F(n -3)
  - F(0) = 1  # Stay put.
  - F(1) = 1  # Take 1-step leap.
  - F(2) = 2  # Take 2 1-step leaps or 1 2-step leap.
  """
  
  from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  
  
  def main():
      pass
  
  
  if __name__ == '__main__':
      main()
  
subject: Add alg_recursive_staircase.py