Count connected components in interval list
Last updated: May 7, 2026
Quick Overview
Given a list of intervals, count the number of connected components formed by these intervals. Two intervals are considered connected if they overlap or touch each other. Your function should take a list of intervals as input and return the total number of connected components.
Grubhub
May 7, 20262
3
3,110 solved
Given a list of intervals, count the number of connected components formed by these intervals. Two intervals are considered connected if they overlap or touch each other. Your function should take a list of intervals as input and return the total number of connected components.
Coding interviews at Grubhub 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 modify your solution to handle streaming input?
- How would you test this solution thoroughly?
- How would your solution change if the input was sorted?
- Can you solve this in a single pass?
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Practice DSA ProblemsSample Answer
Problem Analysis
To solve the problem of counting connected components in a list of intervals, we can identify that this problem can be effectively approached using a sorting strategy followed by a linear scan. The ke...
Approach
- Sort the Intervals: Start by sorting the intervals based on their starting point. If two intervals overlap or touch, they will be adjacent in this sorted list.
- Example: Given intervals [[1...
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