Minimum Number of Trips to Deliver All Packages

Question

## Problem

You are given `n` packages with weights `weights[i]` and a truck with capacity `C`. Each trip the truck can carry any subset of packages as long as the total weight does not exceed `C`. Find the **minimum number of trips** to deliver all packages.

## Example
```
weights = [1, 2, 3, 4], C = 5
Output: 2  -- trips: {1,4} and {2,3}
```

## Constraints
- 1 ≤ n ≤ 20
- 1 ≤ weights[i] ≤ C ≤ 10^4

## Follow-up
What if the truck must return to the depot between trips and each return costs 1 unit of fuel?