Car Fleet
Detailed guide and Python implementation for the 'Car Fleet' problem.
Problem Statement
There are n cars going to the same destination along a one-lane road. The destination is target miles away.
You are given two integer arrays position and speed, both of length n, where position[i] is the position of the ith car and speed[i] is the speed of the ith car (in miles per hour).
A car can never pass another car ahead of it, but it can catch up to it and drive bumper to bumper at the same speed. The faster car will slow down to match the slower car's speed. The distance between these two cars is ignored (they are assumed to be at the same position).
A car fleet is some non-empty set of cars driving at the same position and same speed. A single car is also a car fleet.
Return the number of car fleets that will arrive at the destination.
Write a function carFleet(target: int, position: List[int], speed: List[int]) -> int.
- •n == len(position) == len(speed)
- •1 <= n <= 10^5
- •0 < target <= 10^6
- •0 <= position[i] < target
- •0 < speed[i] <= 10^6
- •All positions are unique
Examples
target = 12, position = [10, 8, 0, 5, 3], speed = [2, 4, 1, 1, 3]
3
Cars at positions 10 and 8: car at 8 catches car at 10 (both arrive at time 1), forming 1 fleet. Car at 0: arrives at time 12. Car at 5: arrives at time 7. Car at 3: arrives at time 3, catches car at 5 at time 7, but car at 5 arrives at 7 too. Cars at 3 and 5 form a fleet. Total: 3 fleets.
target = 10, position = [3], speed = [3]
1
Only one car, so one fleet.
target = 100, position = [0, 2, 4], speed = [4, 2, 1]
1
All cars eventually form a single fleet.
Need a Hint?
Edge Cases to Watch
- Empty input structures
- Single element inputs
- Large numerical bounds
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