BFS on interval list
Last updated: December 24, 2025
Quick Overview
Given a list of intervals, implement a function that uses a breadth-first search (BFS) approach to determine the maximum number of non-overlapping intervals that can be selected. The input will be a list of intervals represented as pairs of integers, and the output should be an integer representing the count of non-overlapping intervals.
Optiver
December 24, 2025250
12
78 solved
Given a list of intervals, implement a function that uses a breadth-first search (BFS) approach to determine the maximum number of non-overlapping intervals that can be selected. The input will be a list of intervals represented as pairs of integers, and the output should be an integer representing the count of non-overlapping intervals.
Coding interviews at Optiver focus on problem-solving approach as much as the final solution. The interviewer wants to see you break down the problem, consider edge cases, and optimize iteratively. Communication throughout the process is key.
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
- How would you test this solution thoroughly?
- Can you solve this in a single pass?
- How would you parallelize this solution?
- What is the worst-case input for your solution?
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Problem Analysis
In this problem, we are tasked with finding the maximum number of non-overlapping intervals from a given list. The key observation here is that intervals can overlap if their start and end points are ...
Approach
- Input Parsing: Start by accepting the list of intervals, e.g.,
intervals = [[1, 2], [2, 3], [3, 4], [1, 3]]. - Sorting: To implement BFS effectively, sort the intervals based on their en...
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