cpp-flashcards/org/study_deck_02/dsa/stack/0853-car-fleet.org

#+PROPERTY: STUDY_DECK_02
* TODO 0853. Car Fleet :medium:
:PROPERTIES:
:NEETCODE: [[file:../../roadmap.org::*0853. Car Fleet][0853. Car Fleet]]
:END:

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.

*Example 1:*

*Input:* target = 12, position = [10,8,0,5,3], speed = [2,4,1,1,3]

*Output:* 3

*Explanation:*

 - 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

*Explanation:*

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

*Explanation:*

 - 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}~

** TODO Approach
Write your approach here.

** TODO Python
#+begin_src python
class Solution:
    def carFleet(self, target: int, position: List[int], speed: List[int]) -> int:
#+end_src

** TODO C++
#+begin_src cpp
class Solution {
public:
    int carFleet(int target, vector<int>& position, vector<int>& speed) {
        
    }
};
#+end_src