mirror of
https://github.com/TheAlgorithms/Python.git
synced 2024-10-06 13:49:30 +00:00
107 lines
2.8 KiB
Python
107 lines
2.8 KiB
Python
"""
|
|
This is pure python implementation of tree traversal algorithms
|
|
"""
|
|
from __future__ import print_function
|
|
import queue
|
|
|
|
try:
|
|
raw_input # Python 2
|
|
except NameError:
|
|
raw_input = input # Python 3
|
|
|
|
|
|
class TreeNode:
|
|
def __init__(self, data):
|
|
self.data = data
|
|
self.right = None
|
|
self.left = None
|
|
|
|
|
|
def build_tree():
|
|
print("\n********Press N to stop entering at any point of time********\n")
|
|
print("Enter the value of the root node: ", end="")
|
|
check = raw_input().strip().lower()
|
|
if check == 'n':
|
|
return None
|
|
data = int(check)
|
|
q = queue.Queue()
|
|
tree_node = TreeNode(data)
|
|
q.put(tree_node)
|
|
while not q.empty():
|
|
node_found = q.get()
|
|
print("Enter the left node of %s: " % node_found.data, end="")
|
|
check = raw_input().strip().lower()
|
|
if check == 'n':
|
|
return tree_node
|
|
left_data = int(check)
|
|
left_node = TreeNode(left_data)
|
|
node_found.left = left_node
|
|
q.put(left_node)
|
|
print("Enter the right node of %s: " % node_found.data, end="")
|
|
check = raw_input().strip().lower()
|
|
if check == 'n':
|
|
return tree_node
|
|
right_data = int(check)
|
|
right_node = TreeNode(right_data)
|
|
node_found.right = right_node
|
|
q.put(right_node)
|
|
|
|
|
|
def pre_order(node):
|
|
if not isinstance(node, TreeNode) or not node:
|
|
return
|
|
print(node.data, end=" ")
|
|
pre_order(node.left)
|
|
pre_order(node.right)
|
|
|
|
|
|
def in_order(node):
|
|
if not isinstance(node, TreeNode) or not node:
|
|
return
|
|
in_order(node.left)
|
|
print(node.data, end=" ")
|
|
in_order(node.right)
|
|
|
|
|
|
def post_order(node):
|
|
if not isinstance(node, TreeNode) or not node:
|
|
return
|
|
post_order(node.left)
|
|
post_order(node.right)
|
|
print(node.data, end=" ")
|
|
|
|
|
|
def level_order(node):
|
|
if not isinstance(node, TreeNode) or not node:
|
|
return
|
|
q = queue.Queue()
|
|
q.put(node)
|
|
while not q.empty():
|
|
node_dequeued = q.get()
|
|
print(node_dequeued.data, end=" ")
|
|
if node_dequeued.left:
|
|
q.put(node_dequeued.left)
|
|
if node_dequeued.right:
|
|
q.put(node_dequeued.right)
|
|
|
|
|
|
if __name__ == '__main__':
|
|
print("\n********* Binary Tree Traversals ************\n")
|
|
|
|
node = build_tree()
|
|
print("\n********* Pre Order Traversal ************")
|
|
pre_order(node)
|
|
print("\n******************************************\n")
|
|
|
|
print("\n********* In Order Traversal ************")
|
|
in_order(node)
|
|
print("\n******************************************\n")
|
|
|
|
print("\n********* Post Order Traversal ************")
|
|
post_order(node)
|
|
print("\n******************************************\n")
|
|
|
|
print("\n********* Level Order Traversal ************")
|
|
level_order(node)
|
|
print("\n******************************************\n")
|