Chapter 623: The Flashlight Bridge Problem

Seeing that both of them were stuck in a stalemate, Zhou Xiaoying ventured tentatively, "I don't think you actually need to block me like this.

"Here's a suggestion. What if we both just do our own thing?

"That way we can both earn extra returns by smuggling Contraband.

"You'd definitely move more than me, so you'd come out ahead either way. It has to be better than the two of us just standing here doing nothing."

Huang Shengjie was quiet for a moment, then shook his head.

"No.

"If we each go off separately, we'd be at opposite ends of the field with the prison structure between us, completely out of each other's sight.

"You could do anything, and I'd have no way of knowing.

"I can't immediately think of what the specific problem would be, but I'm not comfortable with it.

"If neither of us smuggles Contraband, the situation is fair.

"Even if I have the physical edge and trading one-for-one is slightly to my disadvantage, I think that's completely acceptable."

Zhou Xiaoying deflated a little, "You're..."

"Fine. Then we just stay here, and neither of us moves."

Her eyes drifted past Huang Shengjie to the narrow barred windows on the distant prison wall, lingering there with some reluctance before she finally let it go.

Huang Shengjie was quiet for a moment, then said, with genuine curiosity, "Actually, the reason I've been keeping you here isn't purely about the game.

"I want to ask you something.

"After you returned to the community, how have things been with the drug dependency issue?"

Zhou Xiaoying's expression changed, "Aren't you asking a question you already know the answer to?

"You should already know perfectly well."

Huang Shengjie was not entirely sure and asked carefully, "You mean, are you also trying to go through withdrawal, like I am?"

Zhou Xiaoying's eyes went wide, "Withdrawal? Are you serious? Is that even possible?

"When you wake up in the middle of the night in agony, and the medication is right there within reach, can you actually hold yourself back?

"Even if you're made of iron and your willpower is extraordinary, that has to have a limit!"

Huang Shengjie's suspicion had been confirmed.

He looked at her steadily and said, "It sounds like the situations in our two communities really are very different.

"I'm all the more certain now that talking to you about this is the right thing to do.

"Community 23 has made no attempt to control the medications at all, so you're still taking them. Is that right?

"But Community 2's situation is completely different.

"Would you like to hear about it?"

Zhou Xiaoying stared at Huang Shengjie with an expression of disbelief, then gave a slow, small nod.

Earlier, at the entrance to Community 2's Raw Materials Warehouse.

Zhou Wanlin's fingers moved quickly across the display screen, and she finally completed the entire steam train procedure with just enough time to spare before the loading phase ended.

She let out a quiet breath.

"There. That should do it.

"This game seems to be mainly testing logistics planning and the speed at which you can operate the equipment, which is just barely within my area of strength."

She took one more look over the train's entire cargo system.

Raw materials purchased with Gold Pounds in the warehouse were delivered via conveyor belt to the platform, where they waited to be loaded.

First, a dedicated sorting mechanism arranged them according to the material ratios Zhou Wanlin had set.

If Zhou Wanlin had configured the ratio of 'Food,' 'Medications,' and 'Miscellaneous Goods' to 3:3:1, for example, the sorting mechanism would arrange the materials in strict sequence: three Food, three Medications, one Miscellaneous Good, and so on.

Of course, she could also adjust the order manually.

While the materials were heavy, handling a single unit was manageable enough.

After sorting, the materials were repackaged so that the opposing community's inspector could not determine the category from the packaging's appearance.

Finally, a fixed steam-powered crane loaded the materials onto the train's cargo cars, stacking them neatly and flush.

The steam engine gave a hissing whistle and lurched into motion, carrying cargo cars numbered '1' and '2,' and rattled steadily along the track toward Community 23's Inspection Room.

The train moved at a modest pace. Under the game rules, its speed was determined by whichever cargo car was slowest, meaning it would take 2 minutes to reach the platform junction at the opposing Inspection Room.

After a short wait, the steam train arrived at the Inspection Room platform, dropped off car number 2, and rattled back the way it had come.

The return trip carried only car number 1, which made it considerably faster, arriving back in just 1 minute.

Zhou Wanlin still felt slightly uncertain, and ran through the sequence once more on the screen to double-check her calculations.

"Right. That should be correct. This is the optimal solution to the flashlight bridge problem.

"It's not a particularly difficult problem. Even if you've never heard of it specifically, working through it carefully with enough time should lead you there.

"The preparation time was admittedly tight, and you also have to complete the sorting and operations on the screen, so I wonder what kind of player the other community has handling their cargo, and whether they'll arrive at the right answer.

"Either way, my arrangement should be solid. As long as I'm not dragging everyone down, that's good enough."

After reading through the rules, Zhou Wanlin had immediately recognised that the underlying logic was a classic type of puzzle, the flashlight bridge problem.

It was not a particularly difficult problem and occasionally appeared in written tests for certain companies.

In this game's version, the goal was to get all five cargo cars to the other side in as little time as possible.

If all five cars could not be delivered within the allotted time, the system would only send the odd-numbered materials through for inspection and return the even-numbered ones, effectively halving the shipment.

Among the rules, one in particular was critical: the train could not run empty.

Every attached cargo car had to be fully loaded, and the train had to carry at least one car at all times while running. If the train ran empty, it would shut down entirely, effectively wasting that entire round.

In order to get all five cars across, one car would always have to remain coupled to the engine for the return trip.

The speed of that return car determined how quickly the engine could come back. The slower the car, the longer the return journey, and the more time was wasted.

The natural instinct for most people, then, was to always send car '1' back on the return trips, compressing the return time to a minimum.

But if car '1' was always used for returns, delivering all five cars, numbered '1,' '2,' '6,' '7,' and '12,' would take 2+1+6+1+7+1+12 = 30 minutes in total.

And while each round was exactly 30 minutes long, the first 2 minutes were loading time and the last 2 minutes were inspection time. The actual transport window was only 26 minutes, which simply wasn't enough.

To minimise the total time, the larger, slower cars had to be grouped together and sent across in a single trip rather than separately, while a faster car was used to 'bridge' the trips.

After a quick mental calculation before the game began, Zhou Wanlin had worked out the optimal sequence:

Cars '1' and '2' cross together. Car '1' returns. Cars '7' and '12' cross together. Car '2' returns. Cars '6' and '1' cross together. Car '1' returns. Cars '1' and '2' cross together.

The total time: 2+1+12+2+6+1+2 = 26 minutes.

All five cars would arrive, all 28 units of raw material would enter the inspection process, and compared to any imperfect arrangement, twice as much cargo would be delivered.

Zhou Wanlin did not think this was a particularly difficult problem. Even if the opposing community's player didn't arrive at the solution in time for Round One due to insufficient thinking time, they would almost certainly work it out and adjust in a later round.

If the opposing community had also reached this solution before Round One and completed the corresponding setup, both sides would most likely end up at a draw.