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How to Solve Longest Uploaded Prefix Problem
Master the Longest Uploaded Prefix LeetCode problem with undetectable real-time assistance. Get instant solutions and explanations during your coding interviews.
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Start Free for WindowsMedium#2424
LeetCode ProblemLongest Uploaded Prefix
You are given a stream of n videos, each represented by a distinct number from 1 to n that you need to "upload" to a server. You need to implement a data structure that calculates the length of the longest uploaded prefix at various points in the upload process. We consider i to be an uploaded prefix if all videos in the range 1 to i (inclusive) have been uploaded to the server. The longest uploaded prefix is the maximum value of i that satisfies this definition. Implement the LUPrefix class:
Hash TableBinary SearchUnion FindDesignBinary Indexed TreeSegment TreeHeap (Priority Queue)Ordered Set
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Problem Breakdown
Understanding the Longest Uploaded Prefix Problem
Let's break down this LeetCode problem and understand what makes it challenging in interview settings.
Problem Statement
You are given a stream of n videos, each represented by a distinct number from 1 to n that you need to "upload" to a server. You need to implement a data structure that calculates the length of the longest uploaded prefix at various points in the upload process. We consider i to be an uploaded prefix if all videos in the range 1 to i (inclusive) have been uploaded to the server. The longest uploaded prefix is the maximum value of i that satisfies this definition. Implement the LUPrefix class:
MediumProblem #2424
LeetCodeLongest Uploaded Prefix
Related Topics
Hash TableBinary SearchUnion FindDesignBinary Indexed TreeSegment TreeHeap (Priority Queue)Ordered Set
How Phantom Code Helps
Get real-time assistance for Longest Uploaded Prefix problems during coding interviews. Phantom Code provides instant solutions and explanations.
Examples
# Example 1
Input
—
Output
—
Constraints
1 <= n <= 105
1 <= video <= n
All values of video are distinct.
At most 2 * 105 calls in total will be made to upload and longest.
At least one call will be made to longest.
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Solve Longest Uploaded Prefix — You are given a stream of n videos, each represented by a distinct number from 1...
Here's the optimal approach using Hash Table:
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 Longest Uploaded Prefix and using Phantom Code during coding interviews.
How does Phantom Code help me solve coding problems like Longest Uploaded Prefix 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 Longest Uploaded Prefix?
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 Longest Uploaded Prefix?
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 Longest Uploaded Prefix 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 Longest Uploaded Prefix 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 Longest Uploaded Prefix 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 Longest Uploaded Prefix 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 Longest Uploaded Prefix 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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