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# 0853. Car Fleet

<https://leetcode.com/problems/car-fleet>

## Description

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 array `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 distance between these two cars is ignored (i.e., they are assumed to have the same position).

A car fleet is some non-empty set of cars driving at the same position and same speed. Note that a single car is also a car fleet.

If a car catches up to a car fleet right at the destination point, it will still be considered as one 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 and 8 become a fleet, meeting each other at 12.
The car starting at 0 doesn't catch up to any other car, so it is a fleet by itself.
The cars starting at 5 and 3 become a fleet, meeting each other at 6.
Note that no other cars meet these fleets before the destination, so the answer is 3.
```

**Example 2:**

```
**Input:** target = 10, position = [3], speed = [3]
**Output:** 1
```

**Constraints:**

* `n == position.length == speed.length`
* `1 <= n <= 105`
* `0 < target <= 106`
* `0 <= position[i] < target`
* All the values of `position` are **unique**.
* `0 < speed[i] <= 106`

## ac

```java
```