fuzzle

package com.ronnie.concurrent.part8;import java.util.Set;public interface Puzzle<P,M> {/* * 初始化位置信息 */P initialPositon();/* * 判断是否得到正确的答案 */boolean isGoal(P position);/* * 对于位置position,可能的所有移动. */Set<M> legalMoves(P position);/* * 从position位置进行move移动,得到一个新的位置. */P move(P position,M move);}

package com.ronnie.concurrent.part8;import java.util.LinkedList;import java.util.List;import java.util.concurrent.ConcurrentHashMap;import java.util.concurrent.ConcurrentMap;import java.util.concurrent.CountDownLatch;import java.util.concurrent.ExecutorService;/** * 并行解题.. * 2016-3-12 * @author sima * * @param <P> * @param <M> */public class ConcurrentPuzzleSolver<P,M> {/** * 移动的信息..  */static class Node<P,M> {final P position;//如果move为null,表示不可以再移动.final M move;//上一个节点根据move动作得到节点信息.final Node<P,M> prev;Node(P pos,M move,Node<P,M> node){this.position = pos;this.move = move;this.prev = node;}/* * 该节点走过的所有路程.. */List<M> asMoveList(){List<M> solution = new LinkedList<>();//从一个节点出发.根据相关的规则,得到所有的移动信息.for(Node<P, M> n = this;n.move != null ; n = n.prev){solution.add(0,n.move);}return solution;}}private final Puzzle<P, M> puzzle;private final ExecutorService executor;private final ConcurrentMap<P, Boolean> seen = new ConcurrentHashMap<P, Boolean>();final ValueLatch<Node<P, M>> solution = new ValueLatch<Node<P,M>>();public ConcurrentPuzzleSolver(Puzzle<P, M> p,ExecutorService exec) {this.puzzle = p;this.executor = exec;}public List<M> solve() throws InterruptedException{try{P p = puzzle.initialPositon();executor.execute(newTask(p, null, null));Node<P, M> solnNode = solution.getValue();return (solnNode == null) ? null : solnNode.asMoveList();}finally{executor.shutdown();}}protected Runnable newTask(P p,M m,Node<P,M> node){return new SolveTask(p, m, node);}class SolveTask extends Node<P, M> implements Runnable{SolveTask(P pos, M move, Node<P, M> node) {super(pos, move, node);}@Overridepublic void run() {// 判断是否已经找到满足条件的节点或该节点是否已经被遍历过.if(solution.isSet() || seen.putIfAbsent(position, true) != null)return;if(puzzle.isGoal(position))solution.setValue(this);elsefor(M m : puzzle.legalMoves(position))executor.execute(newTask(puzzle.move(position, m),m,this));}}                                                   }class ValueLatch<T>{private T value = null;private final CountDownLatch done = new CountDownLatch(1);public boolean isSet(){return done.getCount() == 0;}public synchronized void setValue(T newValue){if(!isSet()){this.value = newValue;done.countDown();}}public T getValue() throws InterruptedException{done.await();synchronized (this) {return value;}}}

<pre name="code" class="java">package com.ronnie.concurrent.part8;import java.util.HashSet;import java.util.LinkedList;import java.util.List;import java.util.Set;/** * 串行解题... * 2016-3-11 * @author sima * @param <P> * @param <M> */public class SequentialPuzzleSolve<P,M>{/** * 移动的信息..  */static class Node<P,M> {final P position;//如果move为null,表示不可以再移动.final M move;//上一个节点根据move动作得到节点信息.final Node<P,M> prev;Node(P pos,M move,Node<P,M> node){this.position = pos;this.move = move;this.prev = node;}/* * 一个节点的所有可移动的步骤. */List<M> asMoveList(){List<M> solution = new LinkedList<>();//从一个节点出发.根据相关的规则,得到所有的移动信息.for(Node<P, M> n = this;n.move != null ; n = n.prev){solution.add(0,n.move);}return solution;}}private final Puzzle<P, M> puzzle;//已经遍历过的节点..private final Set<P> seen = new HashSet<>();public SequentialPuzzleSolve(Puzzle<P, M> p) {this.puzzle = p;}public List<M> solve(){P pos = puzzle.initialPositon();return search(new Node<P,M>(pos, null, null));}private List<M> search(Node<P, M> node) {if(!seen.contains(node.position)){seen.add(node.position);if(puzzle.isGoal(node.position))return node.asMoveList();for(M move : puzzle.legalMoves(node.position)){P pos = puzzle.move(node.position, move);// 得到一个新的节点信息.再进行递归遍历即可.Node<P,M> child = new Node<P, M>(pos, move, node);List<M> result = search(child);if(result != null)return result;}}return null;}}