Count maximum path in interval list
Last updated: October 30, 2025
Quick Overview
Given a list of intervals, your task is to count the maximum number of overlapping intervals at any point in time. The input will be a list of intervals represented as pairs of integers, where each pair denotes the start and end of an interval. The output should be a single integer representing the maximum overlap count.
Twitter/X
October 30, 202533
6
3,551 solved
Given a list of intervals, your task is to count the maximum number of overlapping intervals at any point in time. The input will be a list of intervals represented as pairs of integers, where each pair denotes the start and end of an interval. The output should be a single integer representing the maximum overlap count.
This coding problem is frequently asked during Technical Screen at Twitter/X. The interviewer is testing your ability to translate a problem into clean, working code while discussing time and space complexity. Twitter/X expects candidates to write production-quality code, not just solve the puzzle.
What the Interviewer Expects
- Identify the correct data structure and algorithm for the problem
- Write clean, bug-free code with proper variable naming
- Analyze time and space complexity correctly
- Handle basic edge cases (empty input, single element)
- Communicate your thought process while coding
Key Topics to Cover
How to Approach This
- Clarify input constraints and edge cases before writing code.
- Walk through your approach verbally and confirm with the interviewer before coding.
- Start with a brute force solution, then optimize. Mention time and space complexity.
- Test your solution with examples, including edge cases like empty input or duplicates.
- Consider common patterns: sliding window, two pointers, hash map, BFS/DFS, dynamic programming.
Possible Follow-up Questions
- Can you optimize the space complexity of your solution?
- How would you parallelize this solution?
- How would you test this solution thoroughly?
- Can you solve this in a single pass?
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Practice DSA ProblemsSample Answer
Problem Analysis
To solve the problem of counting the maximum number of overlapping intervals, we can utilize a sorting and two-pointer approach. The problem essentially revolves around understanding how intervals ove...
Approach
- Transform the Intervals: Create a list of events from the intervals. Each interval [start, end] generates two events: (start, +1) and (end, -1). The +1 indicates the start of an interval (an in...
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