Practice AI, Minimax with "nine men's morris"

Learning Opportunities

This puzzle can be solved using the following concepts. Practice using these concepts and improve your skills.

Minimax

Statement

This is a Community Contribution game.

For this challenge, two leagues are available. There are no rule or game changes between the leagues.

Nine men's morris is a classical strategic board game, like checkers or chess. More information on Wikipedia.

Goal

The game is based on a grid with 24 fields organized on X-axes A..G and Y-axes 1..7

Board

In Debug the field positions are shown on the board.

The game is played in 3 phases:

Placing Each player has 9 stones. On each turn a player place one of his stones on a vacant field.
Moving When all 18 stones are placed, the player can move one stone/round to an adjacent vacant field.
Flying Once a player has only three stones left, he can move a stone to any vacant position on the board and not just to an adjacent vacant field.

Capture
When a player forms a mill by placement or movement, he must take an opponent stone. A mill means three stones from the player forms a horizontal or vertical line.

The order to take a stone is first only opponents stones not connected in a mill. When all opponent stones are connected in a mill, the player can take any stone from the opponent

Winning

The player who takes all but 2 stones from the opponent or prevents the opponent to do a legal move next turn, wins.

Draw

After 200 turns when no player has won, the game is declared as draw.

Commands

A separator ";" is used between action and fields.

Place stone

PLACE ; field1
PLACE: Command to place a stone.
field1: Field on the board to place the stone. It must be vacant.
example: PLACE;A1

PLACE&TAKE ; field1 ; field2
PLACE&TAKE: Command to place a stone with mill. This command must be used when placing and forming a mill.
field1: Field on the board to place the stone. It must be vacant.
field2: Field on the board with the opponent's stone to take.
example: PLACE&TAKE;A1;D1

Move stone

MOVE ; field1 ; field2
MOVE: Command to move a stone.
field1: Field on the board containing the stone the player wants to move.
field2: Field on the board to move the stone to. It must be a vacant and adjacent field.
example: MOVE;A1;D1

MOVE&TAKE ; field1 ; field2 ; field3
MOVE&TAKE: Command to move a stone with mill. This command must be used when moving and forming a mill.
field1: Field on the board containing the stone the player wants to move.
field2: Field on the board to move the stone to. It must be vacant and adjusting to field1.
field3: Field on the board with the opponent's stone to take.
example: MOVE&TAKE;A1;D1;D2

Flying

MOVE ; field1 ; field2
MOVE: Command to move a stone.
field1: Field on the board containing the stone the player wants to move.
field2: Field on the board to move the stone to. It can be any field on the board but it must be vacant.
example: MOVE;A1;D1

MOVE&TAKE ; field1 ; field2 ; field3
MOVE&TAKE: Command to move a stone with mill. This command must be used when moving and forming a mill.
field1: Field on the board containing the stone the player wants to move.
field2: Field on the board to move the stone to. It can be any free field on the board.
field3: Field on the board with the opponent's stone to take.
example: MOVE&TAKE;A1;D1;D2

Game Input

Initialization Input

First line playerId Int Integer value for playerId (0,1)

Next line fields Int number of fields (24) on the board

Next X lines (fields) neighbors String One field per line in in format: field ":" and it's adjusting fields separated with ";" as example: A1:A4;D1

Input for one game turn

First line opMove String Last move of the opponent. In case of no move yet done (first player on first move), it returns -

Next line board String The current board listed as: field and state(0:Player0 | 1:Player1 | 2:Empty) in format field: state separated by ";" in single string.

Next line nbr int Number of valid commands provided as input.

Next X lines (nbr) command String One command per line in in format COMMAND and the corresponding fields separated with ";" as example: PLACE;A1

Output for one game turn

Line 1: command String One single line containing one COMMAND and the corresponding fields separated with ";"

Victory Conditions

Take an opponent stone and your opponent has only 2 stones on the board.
Block all of opponents stones, to do a valid move.

Loss Conditions

Not responding in time (50ms).
Provide an invalid command.
Provide an invalid move or field (invalid stone selected, invalid destination field provided).
Capture a wrong stone, or not capturing when forming a mill.

If after 200 moves no one has won, the game is declared a draw.

Join

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