652. Find Duplicate Subtrees
Medium
30 Points
Hash Table
Tree
Depth-First Search
Binary Tree
Given the root of a binary tree, return all duplicate subtrees.
For each kind of duplicate subtrees, you only need to return the root node of any one of them.
Two trees are duplicate if they have the same structure with the same node values.
Examples
Example 1
Input: root = [1,2,3,4,null,2,4,null,null,4]
Output: [[2,4],[4]]
Example 2
Input: root = [2,1,1]
Output: [[1]]
Example 3
Input: root = [2,2,2,3,null,3,null]
Output: [[2,3],[3]]
Constraints
The number of the nodes in the tree will be in the range [1, 5000]-200 <= Node.val <= 200
652. Find Duplicate Subtrees
Medium
30 Points
Hash Table
Tree
Depth-First Search
Binary Tree
Given the root of a binary tree, return all duplicate subtrees.
For each kind of duplicate subtrees, you only need to return the root node of any one of them.
Two trees are duplicate if they have the same structure with the same node values.
Examples
Example 1
Input: root = [1,2,3,4,null,2,4,null,null,4]
Output: [[2,4],[4]]
Example 2
Input: root = [2,1,1]
Output: [[1]]
Example 3
Input: root = [2,2,2,3,null,3,null]
Output: [[2,3],[3]]
Constraints
The number of the nodes in the tree will be in the range [1, 5000]-200 <= Node.val <= 200