#+ANKI_DECK: 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& position, vector& speed) { } }; #+end_src