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How to Solve Length of Longest Fibonacci Subsequence Problem
Master the Length of Longest Fibonacci Subsequence LeetCode problem with undetectable real-time assistance. Get instant solutions and explanations during your coding interviews.
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Start Free for WindowsMedium#873
LeetCode ProblemLength of Longest Fibonacci Subsequence
A sequence x1, x2, ..., xn is Fibonacci-like if: Given a strictly increasing array arr of positive integers forming a sequence, return the length of the longest Fibonacci-like subsequence of arr. If one does not exist, return 0. A subsequence is derived from another sequence arr by deleting any number of elements (including none) from arr, without changing the order of the remaining elements. For example, [3, 5, 8] is a subsequence of [3, 4, 5, 6, 7, 8].
ArrayHash TableDynamic Programming
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Problem Breakdown
Understanding the Length of Longest Fibonacci Subsequence Problem
Let's break down this LeetCode problem and understand what makes it challenging in interview settings.
Problem Statement
A sequence x1, x2, ..., xn is Fibonacci-like if: Given a strictly increasing array arr of positive integers forming a sequence, return the length of the longest Fibonacci-like subsequence of arr. If one does not exist, return 0. A subsequence is derived from another sequence arr by deleting any number of elements (including none) from arr, without changing the order of the remaining elements. For example, [3, 5, 8] is a subsequence of [3, 4, 5, 6, 7, 8].
MediumProblem #873
LeetCodeLength of Longest Fibonacci Subsequence
Related Topics
ArrayHash TableDynamic Programming
How Phantom Code Helps
Get real-time assistance for Length of Longest Fibonacci Subsequence problems during coding interviews. Phantom Code provides instant solutions and explanations.
Examples
# Example 1
Input
arr = [1,2,3,4,5,6,7,8]
Output
5
# Example 2
Input
arr = [1,3,7,11,12,14,18]
Output
3
Constraints
3 <= arr.length <= 1000
1 <= arr[i] < arr[i + 1] <= 109
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Solve Length of Longest Fibonacci Subsequence — A sequence x1, x2, ..., xn is Fibonacci-like if: Given a strictly increasing arr...
Here's the optimal approach using Array:
def solve(input):
# Optimal O(n) solution
return result
Time: O(n) | Space: O(n)
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Frequently Asked Questions
Common questions about solving Length of Longest Fibonacci Subsequence and using Phantom Code during coding interviews.
How does Phantom Code help me solve coding problems like Length of Longest Fibonacci Subsequence 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 Length of Longest Fibonacci Subsequence?
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.
Can Phantom Code help me communicate my solution for problems like Length of Longest Fibonacci Subsequence?
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 Length of Longest Fibonacci Subsequence 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 Length of Longest Fibonacci Subsequence 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 Length of Longest Fibonacci Subsequence 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 Length of Longest Fibonacci Subsequence 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 Length of Longest Fibonacci Subsequence 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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