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30 lines
716 B
Python
30 lines
716 B
Python
#!/usr/bin/env python3
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# -*- coding: utf-8 -*-
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# author: bt3gl
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'''
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Given a binary tree, find the lowest common ancestor (LCA) of two given nodes in the tree.
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'''
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class Tree:
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def lowest_common_ancestor(self, root: 'TreeNode', p: 'TreeNode', q: 'TreeNode') -> 'TreeNode':
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def dfs(root, p, q):
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if not root:
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return False
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left = dfs(root.left, p, q)
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right = dfs(root.right, p, q)
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mid = root == p or root == q
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if mid + left + right >= 2:
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self.answer = root
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return left or right or mid
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dfs(root, p, q)
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return self.answer
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