PrintTree

Nodes

class Node(object):
  def __init__(self, value, left=None, right=None):
    self.value = value
    self.left = left
    self.right = right
    
def printTree(rootNode):
  printTreeInternal([rootNode], 1, maxLevel(rootNode))

def printWhitespaces(count):
  whitesp = ""
  for i in range(count):
    whitesp += " "
  return whitesp

def maxLevel(node):
  if node is None:
    return 0
  else:
    return max(maxLevel(node.left), maxLevel(node.right))+1

def isAllElementsNull(list):
  for ea in list:
    if not(ea == None):
      return False
  return True

def printTreeInternal(nodeList, level, maxLevel):
  
  if (not nodeList) or (isAllElementsNull(nodeList)):
    return
  
  floor = maxLevel - level
  endgeLines = 2 ** max(floor - 1, 0)
  firstSpaces = (2 ** floor) - 1;
  betweenSpaces = (2 ** (floor + 1)) - 1;

  buffer = printWhitespaces(firstSpaces)

  nodeListNextLevel = []
  for node in nodeList:
    if (not (node is None)):
      buffer += str(node.value)
      nodeListNextLevel.append(node.left)
      nodeListNextLevel.append(node.right)
    else:
      nodeListNextLevel.append(None)
      nodeListNextLevel.append(None)
      buffer += " "
    buffer += printWhitespaces(betweenSpaces)
  print buffer
  buffer = ""

  for i in range(1, endgeLines+1):
    for j in range(len(nodeList)):

      buffer += printWhitespaces(firstSpaces - i)
      if nodeList[j] == None:
        buffer += printWhitespaces(endgeLines + endgeLines + i + 1)
        continue
      
      if not (nodeList[j].left == None):
        buffer += "/"
      else:
        buffer += printWhitespaces(1);
      
      buffer += printWhitespaces(i + i - 1);

      if not (nodeList[j].right == None):
        buffer += "\\"
      else:
        buffer += printWhitespaces(1)

      buffer += printWhitespaces(endgeLines + endgeLines - i)

    print buffer
    buffer = ""
    
  printTreeInternal(nodeListNextLevel, level + 1, maxLevel)
  
t = Node('*', 
          Node('+', 
               Node(4), Node(5)
          ), 
          Node('-', Node(5), Node(6))
    )

q = Node('+',
      Node('-',
        Node(2),
        Node('+', Node(5), Node(8))
      ),
      Node('-', Node(8), Node('*', Node(4), Node(7)))
    )
d = Node(6,
      Node(2,
        Node(1),
        Node(4, Node(3), Node(5))
      ),
      Node(7, Node(8), Node(10, Node(9), Node(11)))
    )