mirror of
https://github.com/krahets/hello-algo.git
synced 2024-12-27 00:06:28 +08:00
43 lines
1.2 KiB
Python
43 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]:
|
||
|
|
"""層序走訪"""
|
||
|
|
# 初始化佇列，加入根節點
|
||
|
|
queue: deque[TreeNode] = deque()
|
||
|
|
queue.append(root)
|
||
|
|
# 初始化一個串列，用於儲存走訪序列
|
||
|
|
res = []
|
||
|
|
while queue:
|
||
|
|
node: TreeNode = queue.popleft() # 隊列出隊
|
||
|
|
res.append(node.val) # 儲存節點值
|
||
|
|
if node.left is not None:
|
||
|
|
queue.append(node.left) # 左子節點入列
|
||
|
|
if node.right is not None:
|
||
|
|
queue.append(node.right) # 右子節點入列
|
||
|
|
return res
|
||
|
|
|
||
|
|
|
||
|
|
"""Driver Code"""
|
||
|
|
if __name__ == "__main__":
|
||
|
|
# 初始化二元樹
|
||
|
|
# 這裡藉助了一個從陣列直接生成二元樹的函式
|
||
|
|
root: TreeNode = list_to_tree(arr=[1, 2, 3, 4, 5, 6, 7])
|
||
|
|
print("\n初始化二元樹\n")
|
||
|
|
print_tree(root)
|
||
|
|
|
||
|
|
# 層序走訪
|
||
|
|
res: list[int] = level_order(root)
|
||
|
|
print("\n層序走訪的節點列印序列 = ", res)
|