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How to Solve The Number of the Smallest Unoccupied Chair Problem
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Medium#1942
LeetCode ProblemThe Number of the Smallest Unoccupied Chair
There is a party where n friends numbered from 0 to n - 1 are attending. There is an infinite number of chairs in this party that are numbered from 0 to infinity. When a friend arrives at the party, they sit on the unoccupied chair with the smallest number. When a friend leaves the party, their chair becomes unoccupied at the moment they leave. If another friend arrives at that same moment, they can sit in that chair. You are given a 0-indexed 2D integer array times where times[i] = [arrivali, leavingi], indicating the arrival and leaving times of the ith friend respectively, and an integer targetFriend. All arrival times are distinct. Return the chair number that the friend numbered targetFriend will sit on.
ArrayHash TableHeap (Priority Queue)
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Problem Breakdown
Understanding the The Number of the Smallest Unoccupied Chair Problem
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Problem Statement
There is a party where n friends numbered from 0 to n - 1 are attending. There is an infinite number of chairs in this party that are numbered from 0 to infinity. When a friend arrives at the party, they sit on the unoccupied chair with the smallest number. When a friend leaves the party, their chair becomes unoccupied at the moment they leave. If another friend arrives at that same moment, they can sit in that chair. You are given a 0-indexed 2D integer array times where times[i] = [arrivali, leavingi], indicating the arrival and leaving times of the ith friend respectively, and an integer targetFriend. All arrival times are distinct. Return the chair number that the friend numbered targetFriend will sit on.
MediumProblem #1942
LeetCodeThe Number of the Smallest Unoccupied Chair
Related Topics
ArrayHash TableHeap (Priority Queue)
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Examples
# Example 1
Input
times = [[1,4],[2,3],[4,6]], targetFriend = 1
Output
1
# Example 2
Input
times = [[3,10],[1,5],[2,6]], targetFriend = 0
Output
2
Constraints
n == times.length
2 <= n <= 104
times[i].length == 2
1 <= arrivali < leavingi <= 105
0 <= targetFriend <= n - 1
Each arrivali time is distinct.
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Solve The Number of the Smallest Unoccupied Chair — There is a party where n friends numbered from 0 to n - 1 are attending. There i...
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
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How does Phantom Code AI help me solve coding problems like The Number of the Smallest Unoccupied Chair during interviews?
Phantom Code AI 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 The Number of the Smallest Unoccupied Chair?
Phantom Code AI 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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How does Phantom Code AI assist with different programming languages for The Number of the Smallest Unoccupied Chair type problems?
Phantom Code AI 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 AI help me avoid during The Number of the Smallest Unoccupied Chair interviews?
Phantom Code AI 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.
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How does Phantom Code AI help when I'm struggling with The Number of the Smallest Unoccupied Chair 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.
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