Skip to content
Open
Changes from all commits
Commits
File filter

Filter by extension

Filter by extension

Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
87 changes: 87 additions & 0 deletions solutions/my_solution.txt
Original file line number Diff line number Diff line change
@@ -0,0 +1,87 @@


Steps for Solving the Thirsty Men Problem:

1. Shuffling the Cups:
- The guests will rearrange their cups such that no one holds their own cup.
- To achieve this, they can stand in a circle and pass their cup to the person on their right.
- This ensures that each guest ends up holding a cup that doesn't belong to them.

2. Secure Placement Using Encryption:
- Each guest, say Guest X, will create a secret key that is known only to them and the pourer.
- Guest X will then:
- Ask the owner of the cup they are holding to choose a large random number.
- Encrypt this number using their secret key.
- Perform a modulus operation (`mod N`) on the encrypted result to ensure the number falls within the range of available positions (0 to N-1).
- Place the cup they are holding in the position corresponding to the result of the modulus operation.

3. Validation by the Pourer:
- The pourer, who knows Guest X's secret key, can independently verify that the calculation was done correctly.
- This ensures that Guest X didn’t intentionally place the cup in an incorrect position.

4. Repeat for All Guests:
- This process is repeated for every guest until all cups are placed in the positions determined by the secure computation.

--------------------------

The following question may arise:
Why is it necessary to shuffle the cups in the first place?

Answer:
Shuffling the cups ensures fairness and enforces cooperation. Here's why:

1. Incentive to Follow the Rules:
- When the cups are shuffled, no guest holds their own cup.
- If a guest disobeys the rules, the guest holding their cup will retaliate by refusing to place it on the table.
- As a result, the disobedient guest will have no chance to drink, creating a strong incentive for everyone to follow the rules.

2. Fair Distribution of Responsibilities:
- Without shuffling, some players (e.g., those assigned the middle positions) might refuse to place their own cups because they perceive it as a disadvantage.
- In the shuffled setup, it is not the cup owner but the person holding the cup who is responsible for placing it, ensuring a fair distribution of responsibilities.

--------------------------

Simulation of the process with three players

Players and Initial Setup:
1. Players:
- Player A, Player B, Player C.

2. Cups:
- Each player initially holds their own cup:
- Player A holds Cup A.
- Player B holds Cup B.
- Player C holds Cup C.

3. Shuffling:
The cups are shuffled so no player holds their own cup:
- Player A holds Cup B.
- Player B holds Cup C.
- Player C holds Cup A.

Simulation Steps:

Step 1: Player A’s Turn
- Player A creates a secret key.
- Player A asks the owner of Cup B (Player B) to choose a random number (e.g., 15).
- Player A encrypts the number and calculates the position by performing modulus 3 on the result.
- Result: Player A places Cup B in Position 2.

Step 2: Player B’s Turn
- Player B creates a secret key.
- Player B asks the owner of Cup C (Player C) to choose a random number (e.g., 9).
- Player B encrypts the number and calculates the position by performing modulus 3 on the result.
- Result: Player B places Cup C in Position 0.

Step 3: Player C’s Turn
- At this point, only Position 1 is left.
- Player C places Cup A directly in the remaining position (Position 1).

Final Outcome:
The cups are placed as follows:
- Position 0: Cup C
- Position 1: Cup A
- Position 2: Cup B

This ensures fairness and adherence to the rules. Each player cooperates because no one holds their own cup, and disobedience results in not being able to drink.