It is critical for Amazon Fresh to notify our customers about late deliveries.
Our customers are waiting for their order to arrive, and will be disappointed
if we keep them waiting and show up late.

When you place an order, the delivery goes from our fulfillment center,
stops at a number of customers along the way, before arriving at the final
customer.

[FC] -20m- [C1] -20m- [C2] -10m- [C3]

									|
								10m
									|
								[C4]

Leave [FC] @ 7:00am
Deliver [C1] by 7:30am (it takes 20m to go from [FC] to [C1],
we arrive @ 7:20am, this order is on time)
Deliver [C2] by 7:30am (it takes 20m to go from [C1] to [C2],
we arrive @ 7:40am, this order is late)
Deliver [C3] by 8:00am (it takes 10m to go from [C2] to [C3],
we arrive @ 7:50am, this order is on time)
Deliver [C4] by 8:00am (it takes 10m to go from [C3] to [C2],
and an additional 10m to go from [C2] to [C4],
we arrive @ 8:10am, this order is late)

Build a system that can detect which deliveries won't make it to the
customer on time.