1379. Find a Corresponding Node of a Binary Tree in a Clone of That Tree

Medium

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Given two binary trees original and cloned and given a reference to a node target in the original tree.

The cloned tree is a copy of the original tree.

Return a reference to the same node in the cloned tree.

Note that you are not allowed to change any of the two trees or the target node and the answer must be a reference to a node in the cloned tree.

Example 1:

Input: tree = [7,4,3,null,null,6,19], target = 3
Output: 3
Explanation: In all examples the original and cloned trees are shown. The target node is a green node from the original tree. The answer is the yellow node from the cloned tree.

Example 2:

Input: tree = [7], target =  7
Output: 7

Example 3:

Input: tree = [8,null,6,null,5,null,4,null,3,null,2,null,1], target = 4
Output: 4

Constraints:

• The number of nodes in the tree is in the range [1, 104].

• The values of the nodes of the tree are unique.

• target node is a node from the original tree and is not null.

Follow up: Could you solve the problem if repeated values on the tree are allowed?

Solution 1

class Solution:
    def getTargetCopy(self, original: TreeNode, cloned: TreeNode, target: TreeNode) -> TreeNode:
        def recursion(root1, root2):
            if root1:
                recursion(root1.left, root2.left)
                if root1 is target:
                    self.ans = root2
                recursion(root1.right, root2.right)
        recursion(original, cloned)
        return self.ans

Solution 2

# Definition for a binary tree node.
# class TreeNode:
#     def __init__(self, x):
#         self.val = x
#         self.left = None
#         self.right = None

class Solution:
    def getTargetCopy(self, original: TreeNode, cloned: TreeNode, target: TreeNode) -> TreeNode:
        self.target = target
        node1 = self.getNode(original)
        node2 = self.getNode(cloned)
        if self.isSame(node1, node2):
            return node2
        return target
    
    def getNode(self, root):
        if root is None:
            return
        if root.val == self.target.val:
            return root
        return self.getNode(root.left) or self.getNode(root.right)
        
    def isSame(self, root1: TreeNode, root2: TreeNode) -> bool:
        if root1 is None and root2 is None:
            return True
        if root1 is None or root2 is None:
            return False
        return root1.val == root2.val and self.isSame(root1.left, root2.left) and self.isSame(root1.right, root2.right)