hello-algo/en/codes/python/chapter_tree/binary_tree_bfs.py
Yudong Jin 1c0f350ad6
translation: Add Python and Java code for EN version (#1345)
* Add the intial translation of code of all the languages

* test

* revert

* Remove

* Add Python and Java code for EN version
2024-05-06 05:21:51 +08:00

42 lines
1.2 KiB
Python

"""
File: binary_tree_bfs.py
Created Time: 2022-12-20
Author: a16su (lpluls001@gmail.com)
"""
import sys
from pathlib import Path
sys.path.append(str(Path(__file__).parent.parent))
from modules import TreeNode, list_to_tree, print_tree
from collections import deque
def level_order(root: TreeNode | None) -> list[int]:
"""Level-order traversal"""
# Initialize queue, add root node
queue: deque[TreeNode] = deque()
queue.append(root)
# Initialize a list to store the traversal sequence
res = []
while queue:
node: TreeNode = queue.popleft() # Queue dequeues
res.append(node.val) # Save node value
if node.left is not None:
queue.append(node.left) # Left child node enqueues
if node.right is not None:
queue.append(node.right) # Right child node enqueues
return res
"""Driver Code"""
if __name__ == "__main__":
# Initialize binary tree
# Use a specific function to convert an array into a binary tree
root: TreeNode = list_to_tree(arr=[1, 2, 3, 4, 5, 6, 7])
print("\nInitialize binary tree\n")
print_tree(root)
# Level-order traversal
res: list[int] = level_order(root)
print("\nPrint sequence of nodes from level-order traversal = ", res)