Recall & Review
beginner
What is the main goal of the Merge Overlapping Intervals problem?
To combine all intervals that overlap into a single continuous interval, so that the final list has no overlapping intervals.
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beginner
Why do we sort intervals by their start time before merging?
Sorting by start time helps us easily find overlapping intervals by comparing each interval with the previous merged one in order.
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intermediate
In merging intervals, what do we do when the current interval overlaps with the last merged interval?
We update the end of the last merged interval to the maximum end between the two overlapping intervals.
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intermediate
What is the time complexity of the Merge Overlapping Intervals algorithm?
O(n log n) because sorting the intervals takes O(n log n) time, and merging them takes O(n) time.
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beginner
Given intervals [[1,3],[2,6],[8,10],[15,18]], what is the merged output?
The merged intervals are [[1,6],[8,10],[15,18]] because [1,3] and [2,6] overlap and combine into [1,6].
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What is the first step in merging overlapping intervals?
✗ Incorrect
Sorting intervals by their start time helps to easily find and merge overlapping intervals.
If two intervals [1,4] and [3,5] overlap, what is their merged interval?
✗ Incorrect
The merged interval covers from the earliest start (1) to the latest end (5).
What do you do if the current interval does NOT overlap with the last merged interval?
✗ Incorrect
If there is no overlap, the current interval is added as a separate interval.
What is the output of merging [[1,2],[3,4],[5,6]]?
✗ Incorrect
None of the intervals overlap, so the output is the same as input.
What data structure is commonly used to store the merged intervals during the process?
✗ Incorrect
A list or array is used to store merged intervals in order.
Explain step-by-step how to merge overlapping intervals given a list of intervals.
Think about sorting first and then checking overlaps one by one.
You got /5 concepts.
Describe why sorting intervals is important before merging them.
Consider how unordered intervals would complicate merging.
You got /4 concepts.