Battleship Guessing and Placement Algorithms

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BattleshipGuessing and Placement Algorithms

• Gemma Francisco
• Department of ICS
• University of California, Irvine

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Guessing Search and Sink Modes

• Search Mode
• Must search in different areas to find a ship
  part
• Enters this mode at the beginning of the game and
  after a ship has been sunk
• Sink Mode
• Enters this mode after a ship part has been found
• Knows generally where a ship is located
• Initially does not know orientation
• Stays in sink mode until receives notification
  that the ship has been sunk

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Non-Learning Algorithm

• Chooses guessing spaces randomly
• Accepts any guess as long as it is valid
• Chooses ship location randomly
• Accepts location as long as the ship fits

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2 by 2 Average Square Algorithm

• Uses historical data from past games
• Evaluates the average amount of times a ship has
  been placed in each square
• Further averages 2 by 2 squares
• Guess on two out of the four squares in each area
  diagonally
• Has a counterpart ship placement algorithm
• Evaluates average for areas from opponents
  guessing in past games
• Attempts to place the ships in not commonly
  guessed areas

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2 by 2 Average Square Algorithm
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Smallest Average Placement

• Examines all possible placements
• Takes the average of the number of times the
  opponent has guessed in each square of the
  prospective placement
• Begins with the smallest ship

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Example

• Below is the example data
• The tables on the right show the possible moves
  that the algorithm considers

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N-Square Size Placement

• For each ship of size n, take the average number
  of times the opponent has guessed in each n by n
  square
• Place the ship randomly within the square with
  the smallest average.