Package g0901_1000.s0971_flip_binary_tree_to_match_preorder_traversal

Class Solution

java.lang.Object

g0901_1000.s0971_flip_binary_tree_to_match_preorder_traversal.Solution

public class Solution
extends Object

971 - Flip Binary Tree To Match Preorder Traversal\. Medium You are given the `root` of a binary tree with `n` nodes, where each node is uniquely assigned a value from `1` to `n`. You are also given a sequence of `n` values `voyage`, which is the **desired** [**pre-order traversal** ](https://en.wikipedia.org/wiki/Tree_traversal#Pre-order) of the binary tree. Any node in the binary tree can be **flipped** by swapping its left and right subtrees. For example, flipping node 1 will have the following effect:  Flip the **smallest** number of nodes so that the **pre-order traversal** of the tree **matches** `voyage`. Return _a list of the values of all **flipped** nodes. You may return the answer in **any order**. If it is **impossible** to flip the nodes in the tree to make the pre-order traversal match_ `voyage`_, return the list_ `[-1]`. **Example 1:**  **Input:** root = [1,2], voyage = [2,1] **Output:** [-1] **Explanation:** It is impossible to flip the nodes such that the pre-order traversal matches voyage. **Example 2:**  **Input:** root = [1,2,3], voyage = [1,3,2] **Output:** [1] **Explanation:** Flipping node 1 swaps nodes 2 and 3, so the pre-order traversal matches voyage. **Example 3:**  **Input:** root = [1,2,3], voyage = [1,2,3] **Output:** [] **Explanation:** The tree's pre-order traversal already matches voyage, so no nodes need to be flipped. **Constraints:** * The number of nodes in the tree is `n`. * `n == voyage.length` * `1 <= n <= 100` * `1 <= Node.val, voyage[i] <= n` * All the values in the tree are **unique**. * All the values in `voyage` are **unique**.

Constructor Summary

Constructors

Constructor	Description
Solution()

Method Summary

Modifier and Type	Method	Description
List<Integer>	flipMatchVoyage(TreeNode root, int[] voyage)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

Solution

public Solution()

Method Details

flipMatchVoyage

public List<Integer> flipMatchVoyage(TreeNode root,
 int[] voyage)