TakeAppleForkJoin

gistfile1.txt

package interview;

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.concurrent.ForkJoinPool;
import java.util.concurrent.RecursiveAction;

/**
 * 两个人轮流取苹果 每次只能取1/2/3 谁拿了最后一个谁就获胜
 * 得到所有的取胜拿法
 * Created by zhuguowei on 5/19/17.
 */
public class TakeAppleForkJoin extends RecursiveAction{

    final int total = 25;
    List<String> takeList ;
    int count;
    String takeResult;

    public TakeAppleForkJoin(int count, String takeResult,List<String> takeList) {
        this.count = count;
        this.takeResult = takeResult;
        this.takeList = takeList;
    }

    @Override
    protected void compute() {

        if(count > total){
            return;
        }
        if(count == total){
            if(takeResult.endsWith("1")) {
//                System.out.printf("count: %d, takeResult: %s%n",count,takeResult);
                takeList.add(takeResult.trim());
            }
            return;
        }

        invokeAll(new TakeAppleForkJoin(count+1,takeResult+" 1",takeList),
                new TakeAppleForkJoin(count+2,takeResult+" 2",takeList),
                new TakeAppleForkJoin(count+3,takeResult+" 3",takeList));
    }

    public static void main(String[] args) {
//        final List<String> takeList = new CopyOnWriteArrayList<>();
        long start = System.currentTimeMillis();
        final List<String> takeList = Collections.synchronizedList(new ArrayList<>());
        TakeAppleForkJoin takeAppleTask = new TakeAppleForkJoin(0,"",takeList);
        ForkJoinPool pool = new ForkJoinPool();
        pool.invoke(takeAppleTask);
        long end = System.currentTimeMillis();
        System.out.println(takeAppleTask.takeList.size());
        System.out.printf("took time: %d%n", end-start);
    }
}