Count Fleets Reaching a Common Destination
Company: Amazon
Role: Software Engineer
Category: Coding & Algorithms
Difficulty: medium
Interview Round: Other
### Problem
Cars start at distinct positions below target and move toward it at their positive speeds. A car cannot pass another; after catching a car or fleet it travels with that slower fleet. Catching exactly at target counts as joining. Return how many fleets arrive.
```cpp
class Solution {
public:
int carFleet(int target, vector<int>& position, vector<int>& speed);
};
```
### Examples
**Example 1:**
```text
target = 10, position = [0,5], speed = [2,1]
Output: 1
Explanation: Both reach target at time5, so they form one fleet there.
```
**Example 2:**
```text
target = 10, position = [0,5], speed = [1,1]
Output: 2
Explanation: Equal speeds preserve the gap, and the cars never meet.
```
### Constraints
- Both arrays have the same n in [1,100000].
- Target is in [1,1000000].
- Positions are distinct integers in [0,target-1].
- Speeds are integers in [1,1000000].
### Contract considerations
Preserve no-passing and meeting-at-target semantics.
```hint Read the boundary condition
When can a trailing car reach the destination no later than the fleet ahead?
```
### Boundary reminders
Preserve no-passing and meeting-at-target semantics.
Overview: Count Fleets Reaching a Common Destination. Cars start at distinct positions below target and move toward it at their positive speeds.
