Minimum Time for All Deliveries Given Agent Constraints

Question

## Problem

You have `n` delivery orders at positions on a number line and `k` delivery agents starting at position 0. Each agent moves at speed 1. Find the **minimum time** to complete all deliveries if agents work in parallel.

## Example
```
orders = [2, 5, 9], k = 2
Output: 5  -- agent1: [2,5], agent2: [9] → max time = 5
```

## Constraints
- 1 ≤ k ≤ n ≤ 10^5
- 1 ≤ orders[i] ≤ 10^9

## Approach
Binary search on the answer. For a given time `T`, check if `k` agents can cover all orders greedily.

## Follow-up
Agents can start from any depot location (not just 0). How does your approach change?