MEDIUM NC#134 Blind #39 Intervals
253. Meeting Rooms II
📖 Problem
Given an array of meeting time intervals intervals where intervals[i] = [start_i, end_i], return the minimum number of conference rooms required.
🧠 Visual Learning Aid
1 Model the input into the right structure
2 Choose the core technique and invariant
3 Execute step-by-step with a sample
4 Validate complexity and edge cases
JS/TS Refreshers
- •Array methods (`push`, `pop`, `shift`, `slice`)
- •Object/Map/Set usage patterns
- •Function parameter and return typing
Logical Thinking Concepts
- •Define invariants before coding
- •Check edge cases first (`[]`, single element, duplicates)
- •Estimate time/space before implementation
💡 Approach
- → Sort start and end times separately
- → When meeting starts, need a room
- → When meeting ends, free up a room
- → Track max rooms needed at any point
- → Time: O(n log n), Space: O(n)
🧭 Prerequisites
🛠️ Hints & Pitfalls
Hints
- •Sort start and end times separately
- •When meeting starts, need a room
- •When meeting ends, free up a room
Common Pitfalls
- •Track max rooms needed at any point
- •Time: O(n log n), Space: O(n)
🧪 Test Cases
Hidden tests on submit: 1
Test Case 1
Not run Input:
minMeetingRooms([[0,30],[5,10],[15,20]]); Expected:
2 Test Case 2
Not run Input:
minMeetingRooms([[7,10],[2,4]]); Expected:
1 Test Case 3
Not run Input:
minMeetingRooms([[1,2],[2,3],[3,4]]); Expected:
1 📝 Code Editor
📤 Output