Car Fleet

arraystacksorting

Problem Statement

There are n cars at given miles away from the starting mile 0, traveling to reach the mile target .

You are given two integer arrays position and speed , both of length n , where position[i] is the starting mile of the i ^th car and speed[i] is the speed of the i ^th car in miles per hour.

A car cannot pass another car, but it can catch up and then travel next to it at the speed of the slower car.

A car fleet is a single car or a group of cars driving next to each other. The speed of the car fleet is the minimum speed of any car in the fleet.

If a car catches up to a car fleet at the mile target , it will still be considered as part of the car fleet.

Return the number of car fleets that will arrive at the destination.

Examples

Example 1

Input: target = 12, position = [10,8,0,5,3], speed = [2,4,1,1,3]
Output: 3
The cars starting at 10 (speed 2) and 8 (speed 4) become a fleet, meeting each other at 12. The fleet forms at target . 
 The car starting at 0 (speed 1) does not catch up to any other car, so it is a fleet by itself. 
 The cars starting at 5 (speed 1) and 3 (speed 3) become a fleet, meeting each other at 6. The fleet moves at speed 1 until it reaches target .

Example 2

Input: target = 10, position = [3], speed = [3]
Output: 1
There is only one car, hence there is only one fleet.

Example 3

Input: target = 100, position = [0,2,4], speed = [4,2,1]
Output: 1
The cars starting at 0 (speed 4) and 2 (speed 2) become a fleet, meeting each other at 4. The car starting at 4 (speed 1) travels to 5. 
 Then, the fleet at 4 (speed 2) and the car at position 5 (speed 1) become one fleet, meeting each other at 6. The fleet moves at speed 1 until it reaches target .

Constraints

n == position.length == speed.length

1 <= n <= 10 ^5

0 < target <= 10 ^6

0 <= position[i] < target

All the values of position are unique .

0 < speed[i] <= 10 ^6

🤔

Medium

Difficulty

Topic Info

ModuleDSA

CategoryArray

Sub-topicStack