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How to Solve LFU Cache Problem
Master the LFU Cache LeetCode problem with undetectable real-time assistance. Get instant solutions and explanations during your coding interviews.
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Start Free for WindowsHard#460
LeetCode ProblemLFU Cache
Design and implement a data structure for a Least Frequently Used (LFU) cache. Implement the LFUCache class: To determine the least frequently used key, a use counter is maintained for each key in the cache. The key with the smallest use counter is the least frequently used key. When a key is first inserted into the cache, its use counter is set to 1 (due to the put operation). The use counter for a key in the cache is incremented either a get or put operation is called on it. The functions get and put must each run in O(1) average time complexity.
Hash TableLinked ListDesignDoubly-Linked List
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Problem Breakdown
Understanding the LFU Cache Problem
Let's break down this LeetCode problem and understand what makes it challenging in interview settings.
Problem Statement
Design and implement a data structure for a Least Frequently Used (LFU) cache. Implement the LFUCache class: To determine the least frequently used key, a use counter is maintained for each key in the cache. The key with the smallest use counter is the least frequently used key. When a key is first inserted into the cache, its use counter is set to 1 (due to the put operation). The use counter for a key in the cache is incremented either a get or put operation is called on it. The functions get and put must each run in O(1) average time complexity.
HardProblem #460
LeetCodeLFU Cache
Related Topics
Hash TableLinked ListDesignDoubly-Linked List
How Phantom Code Helps
Get real-time assistance for LFU Cache problems during coding interviews. Phantom Code provides instant solutions and explanations.
Examples
# Example 1
Input
—
Output
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Constraints
1 <= capacity <= 104
0 <= key <= 105
0 <= value <= 109
At most 2 * 105 calls will be made to get and put.
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Solve LFU Cache — Design and implement a data structure for a Least Frequently Used (LFU) cache. I...
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 LFU Cache and using Phantom Code during coding interviews.
How does Phantom Code help me solve coding problems like LFU Cache 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 LFU Cache?
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 LFU Cache?
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 LFU Cache 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 LFU Cache 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 LFU Cache 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 LFU Cache 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 LFU Cache 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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