diff --git a/traversals/binary_tree_traversals.py b/traversals/binary_tree_traversals.py index 393664579..7fd9f7111 100644 --- a/traversals/binary_tree_traversals.py +++ b/traversals/binary_tree_traversals.py @@ -1,14 +1,8 @@ """ 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 +from typing import List class TreeNode: @@ -20,35 +14,31 @@ class TreeNode: 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': + check = input("Enter the value of the root node: ").strip().lower() or "n" + if check == "n": return None - data = int(check) - q = queue.Queue() - tree_node = TreeNode(data) + q: queue.Queue = queue.Queue() + tree_node = TreeNode(int(check)) 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': + msg = "Enter the left node of %s: " % node_found.data + check = input(msg).strip().lower() or "n" + if check == "n": return tree_node - left_data = int(check) - left_node = TreeNode(left_data) + left_node = TreeNode(int(check)) 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': + msg = "Enter the right node of %s: " % node_found.data + check = input(msg).strip().lower() or "n" + if check == "n": return tree_node - right_data = int(check) - right_node = TreeNode(right_data) + right_node = TreeNode(int(check)) node_found.right = right_node q.put(right_node) -def pre_order(node): +def pre_order(node: TreeNode) -> None: if not isinstance(node, TreeNode) or not node: return print(node.data, end=" ") @@ -56,7 +46,7 @@ def pre_order(node): pre_order(node.right) -def in_order(node): +def in_order(node: TreeNode) -> None: if not isinstance(node, TreeNode) or not node: return in_order(node.left) @@ -64,7 +54,7 @@ def in_order(node): in_order(node.right) -def post_order(node): +def post_order(node: TreeNode) -> None: if not isinstance(node, TreeNode) or not node: return post_order(node.left) @@ -72,10 +62,10 @@ def post_order(node): print(node.data, end=" ") -def level_order(node): +def level_order(node: TreeNode) -> None: if not isinstance(node, TreeNode) or not node: return - q = queue.Queue() + q: queue.Queue = queue.Queue() q.put(node) while not q.empty(): node_dequeued = q.get() @@ -86,10 +76,10 @@ def level_order(node): q.put(node_dequeued.right) -def level_order_actual(node): +def level_order_actual(node: TreeNode) -> None: if not isinstance(node, TreeNode) or not node: return - q = queue.Queue() + q: queue.Queue = queue.Queue() q.put(node) while not q.empty(): list = [] @@ -106,10 +96,10 @@ def level_order_actual(node): # iteration version -def pre_order_iter(node): +def pre_order_iter(node: TreeNode) -> None: if not isinstance(node, TreeNode) or not node: return - stack = [] + stack: List[TreeNode] = [] n = node while n or stack: while n: # start from root node, find its left child @@ -122,10 +112,10 @@ def pre_order_iter(node): n = n.right -def in_order_iter(node): +def in_order_iter(node: TreeNode) -> None: if not isinstance(node, TreeNode) or not node: return - stack = [] + stack: List[TreeNode] = [] n = node while n or stack: while n: @@ -136,7 +126,7 @@ def in_order_iter(node): n = n.right -def post_order_iter(node): +def post_order_iter(node: TreeNode) -> None: if not isinstance(node, TreeNode) or not node: return stack1, stack2 = [], [] @@ -153,38 +143,45 @@ def post_order_iter(node): print(stack2.pop().data, end=" ") -if __name__ == '__main__': - print("\n********* Binary Tree Traversals ************\n") +def prompt(s: str = "", width=50, char="*") -> str: + if not s: + return "\n" + width * char + left, extra = divmod(width - len(s) - 2, 2) + return f"{left * char} {s} {(left + extra) * char}" + + +if __name__ == "__main__": + print(prompt("Binary Tree Traversals")) node = build_tree() - print("\n********* Pre Order Traversal ************") + print(prompt("Pre Order Traversal")) pre_order(node) - print("\n******************************************\n") + print(prompt() + "\n") - print("\n********* In Order Traversal ************") + print(prompt("In Order Traversal")) in_order(node) - print("\n******************************************\n") + print(prompt() + "\n") - print("\n********* Post Order Traversal ************") + print(prompt("Post Order Traversal")) post_order(node) - print("\n******************************************\n") + print(prompt() + "\n") - print("\n********* Level Order Traversal ************") + print(prompt("Level Order Traversal")) level_order(node) - print("\n******************************************\n") + print(prompt() + "\n") - print("\n********* Actual Level Order Traversal ************") + print(prompt("Actual Level Order Traversal")) level_order_actual(node) - print("\n******************************************\n") + print("*" * 50 + "\n") - print("\n********* Pre Order Traversal - Iteration Version ************") + print(prompt("Pre Order Traversal - Iteration Version")) pre_order_iter(node) - print("\n******************************************\n") + print(prompt() + "\n") - print("\n********* In Order Traversal - Iteration Version ************") + print(prompt("In Order Traversal - Iteration Version")) in_order_iter(node) - print("\n******************************************\n") + print(prompt() + "\n") - print("\n********* Post Order Traversal - Iteration Version ************") + print(prompt("Post Order Traversal - Iteration Version")) post_order_iter(node) - print("\n******************************************\n") + print(prompt())