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How to Solve Flip Binary Tree To Match Preorder Traversal Problem
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Start Free for WindowsMedium#971
LeetCode ProblemFlip Binary Tree To Match Preorder Traversal
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 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].
TreeDepth-First SearchBinary Tree
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Problem Breakdown
Understanding the Flip Binary Tree To Match Preorder Traversal Problem
Let's break down this LeetCode problem and understand what makes it challenging in interview settings.
Problem Statement
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 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].
MediumProblem #971
LeetCodeFlip Binary Tree To Match Preorder Traversal
Related Topics
TreeDepth-First SearchBinary Tree
How Phantom Code Helps
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Examples
# Example 1
Input
root = [1,2], voyage = [2,1]
Output
[-1]
# Example 2
Input
root = [1,2,3], voyage = [1,3,2]
Output
[1]
# Example 3
Input
root = [1,2,3], voyage = [1,2,3]
Output
[]
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.
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Solve Flip Binary Tree To Match Preorder Traversal — You are given the root of a binary tree with n nodes, where each node is uniquel...
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def solve(input):
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Time: O(n) | Space: O(n)
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Frequently Asked Questions
Common questions about solving Flip Binary Tree To Match Preorder Traversal and using Phantom Code during coding interviews.
How does Phantom Code help me solve coding problems like Flip Binary Tree To Match Preorder Traversal during interviews?
Phantom Code generates complete solutions instantly with proper complexity analysis, letting you focus on explaining your approach and demonstrating problem-solving skills rather than getting stuck on implementation details during high-pressure situations.
What if the interviewer asks follow-up questions or modifications to problems like Flip Binary Tree To Match Preorder Traversal?
Phantom Code adapts in real-time. Screenshot the modified problem or use audio mode to capture the interviewer's follow-up, and get an updated solution within seconds — including edge cases and optimizations.
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Yes. Phantom Code provides step-by-step approach explanations with 3 progressive thoughts, so you can walk through your solution naturally. It also provides time and space complexity analysis to discuss trade-offs.
How does Phantom Code assist with different programming languages for Flip Binary Tree To Match Preorder Traversal type problems?
Phantom Code supports 11 programming languages including Python, Java, C++, JavaScript, TypeScript, Go, Rust, Ruby, Swift, Kotlin, and C#. Set your preferred language and get idiomatic solutions.
What coding mistakes does Phantom Code help me avoid during Flip Binary Tree To Match Preorder Traversal interviews?
Phantom Code catches common mistakes like off-by-one errors, missing edge cases, incorrect base conditions, and suboptimal approaches. It provides clean, well-structured code that handles all edge cases.
Is Phantom Code detectable when solving problems like Flip Binary Tree To Match Preorder Traversal during live interviews?
No. Phantom Code runs as an invisible desktop overlay that doesn't appear in screen shares, recordings, or proctoring software. It works with Zoom, HackerRank, CodeSignal, CoderPad, and all major platforms.
How does Phantom Code help when I'm struggling with Flip Binary Tree To Match Preorder Traversal style questions under pressure?
The AI provides structured guidance: first the approach (what algorithm/data structure to use and why), then the implementation with clean code, and finally complexity analysis. This helps you think clearly even under pressure.
Does Phantom Code work for the coding platforms used in Flip Binary Tree To Match Preorder Traversal interviews?
Yes. Phantom Code works with all major coding platforms including LeetCode, HackerRank, CodeSignal, CoderPad, HackerEarth, and any browser-based coding environment.
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