Train Platform Allocation
Train Platform Allocation problems involve assigning trains to platforms such that no two trains occupy the same platform at the same time. You need to find the minimum number of platforms required.
What You'll Learn
Introduction to Train Platform Allocation
Train Platform Allocation problems involve assigning trains to platforms such that no two trains occupy the same platform at the same time. You need to find the minimum number of platforms required.
Prerequisites
How to Solve Train Platform Allocation Problems
Step 1: List all trains with arrival and departure times
Step 2: Sort all events (arrivals and departures) by time
Step 3: Sweep through events: +1 for arrival, -1 for departure
Step 4: Track maximum concurrent trains
Step 5: This maximum = minimum platforms needed
Example Problem
Example: Trains: T1(9:00-10:00), T2(9:30-11:00), T3(10:00-12:00), T4(11:00-13:00). Minimum platforms? Solution: Step 1: Events: 9:00(+1), 9:30(+1), 10:00(-1,+1), 11:00(-1,+1), 12:00(-1), 13:00(-1) Step 2: Sweep: 9:00→1, 9:30→2, 10:00→2 (after -1 then +1), 11:00→2, 12:00→1, 13:00→0 Step 3: Max concurrent = 2 Answer: 2 platforms
Pro Tips & Tricks
- Treat departure as -1, arrival as +1
- If arrival = departure of another, can use same platform (departure before arrival usually)
- Sort by time; if tie, departures before arrivals
- Maximum value during sweep is answer
Shortcut Methods to Solve Faster
Common Mistakes to Avoid
Practice Worksheets
Practice makes perfect! Work through these worksheets to master Train Platform Allocation. Each worksheet contains 20 questions with detailed explanations. Start from Worksheet 1 and progress through increasing difficulty levels.
Exam Importance
Train Platform Allocation is an important topic for various competitive exams. Here's how frequently it appears:
Ready to Master Train Platform Allocation?
Start with Worksheet 1 and work your way up to expert level! Each worksheet includes: