Merge overlapping intervals
Company: Atlassian
Role: Software Engineer
Category: Coding & Algorithms
Difficulty: medium
Interview Round: Technical Screen
Given an array of closed intervals `intervals`, where each interval is `[start, end]` and `start <= end`, merge all overlapping intervals and return an array of the merged, non-overlapping intervals sorted by start time.
Two intervals `[a, b]` and `[c, d]` overlap if `c <= b` (assuming `a <= c`).
#### Input
- `intervals`: list of `n` intervals
#### Output
- A list of merged intervals.
#### Example
Input: `[[1,3],[2,6],[8,10],[15,18]]`
Output: `[[1,6],[8,10],[15,18]]`
#### Constraints
- `1 ≤ n ≤ 10^5`
- Interval endpoints fit in 32-bit integers.
Quick Answer: This question evaluates understanding of interval manipulation, array processing, and algorithmic efficiency by requiring reasoning about overlapping ranges and proper handling of edge cases.
Merge overlapping closed intervals and return sorted non-overlapping intervals.
Constraints
- Inputs are Python literals matching the function signature.
- Return a deterministic exact-match value.
Examples
Input: ([[1,3],[2,6],[8,10],[15,18]],)
Expected Output: [[1, 6], [8, 10], [15, 18]]
Explanation: Overlapping intervals merge.
Input: ([[1,4],[4,5]],)
Expected Output: [[1, 5]]
Explanation: Touching closed intervals merge.
Input: ([[5,6],[1,2]],)
Expected Output: [[1, 2], [5, 6]]
Explanation: Output is sorted by start.
Hints
- Clarify edge cases before coding.
- Keep the return value deterministic.