What is the optimal time complexity of solving Merge Intervals?

The optimized solution achieves a time complexity of O(n) by using sorting, mathematical shortcuts, or hash table lookups.

What is the auxiliary space complexity for Merge Intervals?

The space complexity is O(n) since we only use a minimal/constant amount of extra memory for tracking variables (or auxiliary space if dynamic structures are allocated).

What are the typical edge cases we must handle in Merge Intervals?

Key edge cases include empty collections, negative or large bounds causing integer overflow, arrays with only one element, or inputs where target criteria are not met.

How can we optimize the brute force approach for Merge Intervals?

Brute force methods often inspect all possible combinations. We optimize this by sorting the input list to enable binary search, or tracking processed items in a set to avoid redundant nested loop lookups.

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Merge Intervals

Learn how to solve the 'Merge Intervals' problem. This detailed resource details brute force and optimized approaches.

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Problem Statement

Easy

Given an array of intervals where intervals[i] = [starti, endi], merge all overlapping intervals, and return an array of the non-overlapping intervals that cover all the intervals in the input.

Write a function merge(intervals: List[List[int]]) -> List[List[int]].

Constraints

•1 <= len(intervals) <= 10^4
•intervals[i].length == 2
•0 <= starti <= endi <= 10^4

Examples

Example 1

Input

intervals = [[1,3],[2,6],[8,10],[15,18]]

Output

[[1,6],[8,10],[15,18]]

Explanation

Intervals [1,3] and [2,6] overlap, merge to [1,6].

Example 2

Input

intervals = [[1,4],[4,5]]

Output

[[1,5]]

Explanation

[1,4] and [4,5] overlap.

Need a Hint?

Analyze the input constraints. Try sorting first (O(n log n)) or using a hash map/set to track seen elements in O(n) time.

Edge Cases to Watch

Empty list or null input variables
Single item lists/arrays
Extremely large input bounds causing integer or stack overflow

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