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Update construct_tree_inorder_postorder.py

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bt3gl 2023-07-30 15:51:43 -07:00 committed by GitHub
parent 0526bb7aee
commit 38cbe1c55b
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1 changed files with 15 additions and 11 deletions
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trees_and_graphs/construct_tree_inorder_postorder.py
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@ -1,10 +1,12 @@
#!/usr/bin/env python3
# -*- coding: utf-8 -*-
# author: bt3gl
# Given two integer arrays inorder and postorder where inorder is the inorder # Given two integer arrays inorder and postorder where inorder is the inorder
# traversal of a binary tree and postorder is the postorder traversal of the # traversal of a binary tree and postorder is the postorder traversal of the
# same tree, construct and return the binary tree. # same tree, construct and return the binary tree.
def build_tree(inorder: list[int], postorder: list[int]) -> Optional[TreeNode]:
def fill_tree(i_left, i_right, inorder_map): def fill_tree(i_left, i_right, inorder_map):
if i_left > i_right: if i_left > i_right:
return None return None
@ -19,7 +21,9 @@ def build_tree(inorder: list[int], postorder: list[int]) -> Optional[TreeNode]:
return root return root
inorder_map = {val: index for index, val in enumerate(inorder)}
def build_tree(inorder: list[int], postorder: list[int]) -> Optional[TreeNode]:
inorder_map = {val: index for index, val in enumerate(inorder)}
return fill_tree(0, len(inorder) - 1, inorder_map) return fill_tree(0, len(inorder) - 1, inorder_map)