CS 3600 Spring 2026


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CS3600 Spring 2026 Tournament Rules

Basics

Each agent controls a worker on an 8x8 chessboard. The agents take turns making moves. After both have had 40 turns, the game is terminated.

Each agent gets a total of 4 minutes to come up with all its moves. If a player runs out of time, they lose the game.

The agent with the most points when the game terminates is the winner. Points are earned through:

  • Priming: When you paint a square with glue, you gain 1 point.
  • Carpeting: When you carpet a line of n primed squares, you gain points per the table below. Either player can step into a carpeted square.

| n | 1 | 2 | 3 | 4 | 5 | 6 | 7 | |--------|----|---|---|---|----|----|----| | Points | -1 | 2 | 4 | 6 | 10 | 15 | 21 |

  • Catching the Rat: If you guess the square where the rat is hidden, you gain 4 points. If you guess incorrectly, you lose 2 points.

Start

Each corner of the map will have blocked squares randomly arranged in either a 3x2, 2x3, or 2x2 rectangle.

Player A moves first. Player B moves second. Both players spawn within the center 4x4 squares in horizontally mirrored positions.

There is a rat hidden in one of the squares.

You are given a 64x64 transition matrix where each cell (x, y) is mapped to a flat index i = y * 8 + x. The matrix defines the rat's movement probabilities:

T(i, j) = P(moving from cell i to cell j)

For any given i, only five entries can be non-zero (the rat staying in place or moving to one of the four adjacent cardinal neighbors), and probabilities always sum to 1.0. The rat can move under blocked squares.

The T table is different for every game but stays constant for the whole game.

Rat headstart: The rat is placed in square (0,0) and moves freely for 1000 moves (following the T table) before the game begins.

Play

Each turn, the agent either:

  • picks a move to perform, or
  • guesses the location of the rat.

Two workers cannot occupy the same square.

Move Types

  1. Plain Step — Simply changes the worker's position in one of the four cardinal directions. You cannot plain step onto a primed square.
  2. Prime Step — Can only happen on a square that is not primed or carpeted. When the worker departs the square, it becomes primed. You cannot prime step onto a primed square.
  3. Carpet Roll of length k — Moves the worker in a straight line over k contiguous primed squares, starting from a square adjacent to the worker's current position, carpeting each square. The worker ends on the k-th (final) square.

Search Move

The worker searches any cell on the map for the rat (the worker itself does not move).

  • If the rat is found: +4 points
  • If the rat is not found: −2 points

The Rat

There is always a rat under the floor of one of the squares.

Before each turn, the rat moves one square in one of the cardinal directions (or stays) according to the T table and makes a noise.

Rat Noises

The rat can make the following noises: squeak, scratch, squeal. The probability depends on the floor type:

| Floor Type | Squeak | Scratch | Squeal | |------------|--------|---------|--------| | Blocked | 0.5 | 0.3 | 0.2 | | Space | 0.7 | 0.15 | 0.15 | | Primed | 0.1 | 0.8 | 0.1 | | Carpet | 0.1 | 0.1 | 0.8 |

Distance Estimate

On your worker's turn, it will hear the rat and receive an estimated Manhattan distance to the rat's square. The distance estimate is noisy:

| Reported Measure | Probability | |--------------------------|-------------| | One less than actual | 0.12 | | Correct | 0.70 | | One more than actual | 0.12 | | Two more than actual | 0.06 |

Your worker will never estimate less than zero. (If the dice roll would produce a negative estimate, you receive an estimate of zero.)

Rat Respawn

As soon as the rat is captured, a new rat is spawned and allowed to run for 1000 steps before the next player is given a turn.

If your opponent guesses on their turn, you will be told what they guessed and whether they were right or not.

Termination Conditions

The game ends under the following conditions:

  • A worker makes an invalid move → the responsible agent loses.
  • An agent runs out of time → that agent loses.
  • Both agents have made all their moves → the worker with the most points wins.

TA Bots

There are 3 reference bots. Once submissions are due, we will reset the ELO of all bots and begin the final tournament:

  • If you are above George in the final rankings you will get at least a 70%.
  • If you are above Albert, you will get at least an 80%.
  • If you are above Carrie, you will get at least a 90%.