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33 lines
776 B
Python
33 lines
776 B
Python
#!/usr/bin/env python3
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# -*- coding: utf-8 -*-
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# author: bt3gl
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# Given the root of a binary tree, return all duplicate subtrees.
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def find_duplicates(root: Optional[Node]) -> list[Optional[Node]]:
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result = []
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counter = {}
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def traverse(node):
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if not node:
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return ""
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rep = ("(" + traverse(node.left) + ")" + \
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str(node.val) + "(" + \
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traverse(node.right) + ")")
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if rep in counter:
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counter[rep] += 1
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else:
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counter[rep] = 1
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if counter[rep] == 2:
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result.append(node)
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return rep
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traverse(root)
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return result
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