Class BoardState

java.lang.Object

topics.branchandbound.utils.Node

topics.branchandbound.rectangles.BoardState

All Implemented Interfaces:

Comparable<Node>

class BoardState
extends Node

Represents a distinct physical configuration of the board within the state space tree. It tracks placed rectangles, calculates the bounding area heuristic, and generates valid subsequent placements.

Field Summary

Fields inherited from class Node

depth, heuristicValue, id, parentId

Constructor Summary

Constructors

Constructor	Description
BoardState(int[][] board, List<Piece> pieces, int depth, UUID parentID)	Constructs a child node representing a subsequent placement state.
BoardState(int boardSize, List<Piece> pieces)	Constructs the root node representing an empty board.

Method Summary

Modifier and Type	Method	Description
void	calculateHeuristicValue()	Computes the bounding box area of all placed pieces.
ArrayList<Node>	expand()	Generates all mathematically valid mathematical configurations extending from the current state by placing the next available piece.
boolean	isSolution()	Determines whether the current node represents a fully resolved configuration.
String	toString()

Methods inherited from class Node

compareTo, equals, getDepth, getHeuristicValue, getId, getParentId, hashCode, initialValuePruneLimit

Methods inherited from class Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Details

BoardState

public BoardState(int boardSize,
 List<Piece> pieces)

Constructs the root node representing an empty board.

Parameters:

boardSize - The dimension of the square board.

pieces - The list of pieces pending placement.

BoardState

public BoardState(int[][] board,
 List<Piece> pieces,
 int depth,
 UUID parentID)

Constructs a child node representing a subsequent placement state.

Parameters:

board - The new board configuration.

pieces - The list of pieces pending placement.

depth - The current depth in the state space tree.

parentID - The unique identifier of the parent node.

Method Details

expand

public ArrayList<Node> expand()

Generates all mathematically valid mathematical configurations extending from the current state by placing the next available piece.

Specified by:

expand in class Node

Returns:

A list containing the resulting child nodes.

calculateHeuristicValue

public void calculateHeuristicValue()

Computes the bounding box area of all placed pieces. This serves as the lower-bound heuristic estimate to prune sub-optimal configurations.

Specified by:

calculateHeuristicValue in class Node

isSolution

public boolean isSolution()

Determines whether the current node represents a fully resolved configuration.

Specified by:

isSolution in class Node

Returns:

true if all pieces have been placed; false otherwise.

toString

public String toString()

Overrides:

toString in class Object