1379.find-a-corresponding-node-of-a-binary-tree-in-a-clone-of-that-tree.cpp

/*
 * @lc app=leetcode id=1379 lang=cpp
 *
 * [1379] Find a Corresponding Node of a Binary Tree in a Clone of That Tree
 *
 * https://leetcode.com/problems/find-a-corresponding-node-of-a-binary-tree-in-a-clone-of-that-tree/description/
 *
 * algorithms
 * Medium (85.60%)
 * Likes:    397
 * Dislikes: 543
 * Total Accepted:    65.9K
 * Total Submissions: 77.8K
 * Testcase Example:  '[7,4,3,null,null,6,19]\n3'
 *
 * 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.
 * 
 */

// @lc code=start
/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
 * };
 */

class Solution {
public:
    TreeNode* getTargetCopy1(TreeNode* original, TreeNode* cloned, TreeNode* target) {
        if (!cloned)
            return nullptr;
        if (original == target) {
            return cloned;
        }
        TreeNode* left = getTargetCopy(original->left, cloned->left, target);
        TreeNode* right = getTargetCopy(original->right, cloned->right, target);
        return left? left : right;
    }
    TreeNode* getTargetCopy(TreeNode* original, TreeNode* cloned, TreeNode* target) {
        stack<TreeNode*> st_o;
        stack<TreeNode*> st_c;
        while (!st_o.empty() || original != nullptr) {
            if (original) {
                st_o.push(original);
                st_c.push(cloned);
                original = original->left;
                cloned = cloned->left;
            } else {
                original = st_o.top();
                st_o.pop();
                cloned = st_c.top();
                st_c.pop();                
                if (original == target)  return cloned;
                cloned = cloned->right;                
                original = original->right;
            }
        }
        return nullptr;
    }
};
// @lc code=end