You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
120 lines
3.5 KiB
120 lines
3.5 KiB
"""
|
|
File: array_binary_tree.py
|
|
Created Time: 2023-07-19
|
|
Author: krahets (krahets@163.com)
|
|
"""
|
|
|
|
import sys
|
|
from pathlib import Path
|
|
|
|
sys.path.append(str(Path(__file__).parent.parent))
|
|
from modules import TreeNode, list_to_tree, print_tree
|
|
|
|
|
|
class ArrayBinaryTree:
|
|
"""Array-based binary tree class"""
|
|
|
|
def __init__(self, arr: list[int | None]):
|
|
"""Constructor"""
|
|
self._tree = list(arr)
|
|
|
|
def size(self):
|
|
"""List capacity"""
|
|
return len(self._tree)
|
|
|
|
def val(self, i: int) -> int | None:
|
|
"""Get the value of the node at index i"""
|
|
# If the index is out of bounds, return None, representing a vacancy
|
|
if i < 0 or i >= self.size():
|
|
return None
|
|
return self._tree[i]
|
|
|
|
def left(self, i: int) -> int | None:
|
|
"""Get the index of the left child of the node at index i"""
|
|
return 2 * i + 1
|
|
|
|
def right(self, i: int) -> int | None:
|
|
"""Get the index of the right child of the node at index i"""
|
|
return 2 * i + 2
|
|
|
|
def parent(self, i: int) -> int | None:
|
|
"""Get the index of the parent of the node at index i"""
|
|
return (i - 1) // 2
|
|
|
|
def level_order(self) -> list[int]:
|
|
"""Level-order traversal"""
|
|
self.res = []
|
|
# Traverse array
|
|
for i in range(self.size()):
|
|
if self.val(i) is not None:
|
|
self.res.append(self.val(i))
|
|
return self.res
|
|
|
|
def dfs(self, i: int, order: str):
|
|
"""Depth-first traversal"""
|
|
if self.val(i) is None:
|
|
return
|
|
# Pre-order traversal
|
|
if order == "pre":
|
|
self.res.append(self.val(i))
|
|
self.dfs(self.left(i), order)
|
|
# In-order traversal
|
|
if order == "in":
|
|
self.res.append(self.val(i))
|
|
self.dfs(self.right(i), order)
|
|
# Post-order traversal
|
|
if order == "post":
|
|
self.res.append(self.val(i))
|
|
|
|
def pre_order(self) -> list[int]:
|
|
"""Pre-order traversal"""
|
|
self.res = []
|
|
self.dfs(0, order="pre")
|
|
return self.res
|
|
|
|
def in_order(self) -> list[int]:
|
|
"""In-order traversal"""
|
|
self.res = []
|
|
self.dfs(0, order="in")
|
|
return self.res
|
|
|
|
def post_order(self) -> list[int]:
|
|
"""Post-order traversal"""
|
|
self.res = []
|
|
self.dfs(0, order="post")
|
|
return self.res
|
|
|
|
|
|
"""Driver Code"""
|
|
if __name__ == "__main__":
|
|
# Initialize binary tree
|
|
# Use a specific function to convert an array into a binary tree
|
|
arr = [1, 2, 3, 4, None, 6, 7, 8, 9, None, None, 12, None, None, 15]
|
|
root = list_to_tree(arr)
|
|
print("\nInitialize binary tree\n")
|
|
print("Array representation of the binary tree:")
|
|
print(arr)
|
|
print("Linked list representation of the binary tree:")
|
|
print_tree(root)
|
|
|
|
# Array-based binary tree class
|
|
abt = ArrayBinaryTree(arr)
|
|
|
|
# Access node
|
|
i = 1
|
|
l, r, p = abt.left(i), abt.right(i), abt.parent(i)
|
|
print(f"\nCurrent node index is {i}, value is {abt.val(i)}")
|
|
print(f"Its left child node index is {l}, value is {abt.val(l)}")
|
|
print(f"Its right child node index is {r}, value is {abt.val(r)}")
|
|
print(f"Its parent node index is {p}, value is {abt.val(p)}")
|
|
|
|
# Traverse tree
|
|
res = abt.level_order()
|
|
print("\nLevel-order traversal is:", res)
|
|
res = abt.pre_order()
|
|
print("Pre-order traversal is:", res)
|
|
res = abt.in_order()
|
|
print("In-order traversal is:", res)
|
|
res = abt.post_order()
|
|
print("Post-order traversal is:", res)
|