Java 101 Chapter 13

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

The following leetcode exercise is called:

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

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.

Follow up: Solve the problem if repeated values on the tree are allowed.

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

Example 4:

Input: tree = [1,2,3,4,5,6,7,8,9,10], target = 5
Output: 5

Example 5:

Input: tree = [1,2,null,3], target = 2
Output: 2

Constraints:

• The number of nodes in the tree is in the range [1, 10^4].
• The values of the nodes of the tree are unique.
• target node is a node from the original tree and is not null.

Solution

For my solution, I could not care less about the original three, instead, we focused on the main parts:

• What makes a node? A node is made up by their holding value, their child/leaves and the parents node or route. Since we do not know the parent route of the given node. We will ignore that property
• How would we traverse the three? Honestly, this is not as relevant, I used a queue and an iterative approach to traverse this three.

My solution in java can be seen below:

/**
 * Definition for a binary tree node.
 * public class TreeNode {
 *     int val;
 *     TreeNode left;
 *     TreeNode right;
 *     TreeNode(int x) { val = x; }
 * }
 */
class Solution {
    public final TreeNode getTargetCopy(final TreeNode original, final TreeNode cloned, final TreeNode target) {
        //Queue<TreeNode> queue= new LinkedList<>
        Queue<TreeNode> q = new LinkedList<TreeNode>();
        q.add(cloned);
        while(q.size() > 0){
            TreeNode tmp = q.poll();
            if( areNodeSame(target, tmp) ) return tmp;
            if(tmp.left != null ) q.add(tmp.left);
            if(tmp.right != null ) q.add(tmp.right);
        }
        return null;
    }
    public boolean areNodeSame(TreeNode node, TreeNode anotherNode){
        if(node != null &&  anotherNode != null && node.val == anotherNode.val ){
            if(node.left == null && anotherNode.left != null) return false;
            if(node.left != null && anotherNode.left == null) return false;
            if(node.left != null && anotherNode.left != null && node.left.val != anotherNode.left.val) return false;
            
            if(node.right == null && anotherNode.right != null) return false;
            if(node.right != null && anotherNode.right == null) return false;
            if(node.right != null && anotherNode.right != null && node.right.val != anotherNode.right.val) return false;
            
            return true;
        }return false;
    }
}