深搜算法：倒油/面向对象的思想来做

题目：有一位厨师要从盛12斤油（a桶）的桶中倒出6斤油来，可是手边只有盛8斤油（b桶）和盛5斤油（c桶）的两个桶，问如何操作才能将6斤取出来呢？

下面为JAVA实现代码：
主类：

package cn.hncu.oil.dfs1;

import cn.hncu.oil.common.Bucket;
import cn.hncu.oil.common.DumpCase;
import cn.hncu.oil.common.Myset;

public class DumpOilDFS {
    public static void main(String[] args) {

        Bucket buckets[] = new Bucket[3];
        buckets[0] = new Bucket(12, 12);
        buckets[1] = new Bucket(8, 0);
        buckets[2] = new Bucket(5, 0);

        DumpCase u = new DumpCase(buckets);
        Myset caseset = new Myset();
        caseset.add(u);

        dfs(u,caseset);

    }

    private static void dfs(DumpCase u0, Myset caseset) {

        for(Bucket bucket: u0.getBucket()){
            if(bucket.getNow()==6){
                //System.out.println("find a case");
                print(u0);
                return;
            }
        }

        int n = u0.getBucket().length;//桶的个数
        DumpCase u = new DumpCase(u0);
        //用备份节点去搜
        //遍历所有的DumpCase: 依次让桶i向j倒
        for(int i=0;i<n;i++){
            for(int j=0;j<n;j++){
                if(i==j){//不能自己给自己的桶倒油
                    continue;
                }
                //算出桶i给j倒时，能倒多少-->temp
                int temp = u.getBucket()[i].canOut();
                if(u.getBucket()[j].canIn()<u.getBucket()[i].canOut()){
                    temp = u.getBucket()[j].canIn();
                }
                //倒油
                u.getBucket()[i].out(temp);
                u.getBucket()[j].in(temp);

                //判断该情况是否已经出现过了//如果存在，要还原(把油倒回去)
                if(caseset.contains(u)){
                    u.getBucket()[i].in(temp);
                    u.getBucket()[j].out(temp);
                    continue;
                }

                DumpCase v = new DumpCase(u);
                v.setParent(u0);
                caseset.add(v);
                //System.out.println(a);
                dfs(v,caseset);

                u.getBucket()[i].in(temp);
                u.getBucket()[j].out(temp);

            }
        }

    }

    private static void print(DumpCase u0) {
        Myset set  =new Myset();
        set.add(u0);
        DumpCase v =u0.getParent();
        while(v!=null){
            set.add(v);
            //System.out.println(v.getBucket()[0].getNow()+","+v.getBucket()[1].getNow()+","+v.getBucket()[2].getNow());
            v= v.getParent();
        }
        System.out.println("------------");
        //System.out.println("12,0,0");
        Object objs[] = set.getAll();

        for(int i=objs.length-1;i>=0;i--){
            DumpCase u =(DumpCase) objs[i];
            System.out.println(u.getBucket()[0].getNow()+","+u.getBucket()[1].getNow()+","+u.getBucket()[2].getNow());
        }

    }

}

DumpCase 类：

package cn.hncu.oil.common;

import java.util.Arrays;

public class DumpCase {
    Bucket buckets[];
    DumpCase parent = null;

    public DumpCase(){

    }

    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result + Arrays.hashCode(buckets);
        return result;
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj)
            return true;
        if (obj == null)
            return false;
        if (getClass() != obj.getClass())
            return false;
        DumpCase other = (DumpCase) obj;
        if (!Arrays.equals(buckets, other.buckets))
            return false;
        return true;
    }

    public DumpCase(Bucket buckets[]){
        this.buckets = buckets;
    }

    public DumpCase(DumpCase u) {//必须要深拷贝
        this.buckets = new Bucket[u.getBucket().length];
        for(int i=0;i<u.getBucket().length;i++){
            this.buckets[i] = new Bucket(0, 0);
            this.buckets[i].max=u.buckets[i].max;
            this.buckets[i].now=u.buckets[i].now;
        }

    }

    public Bucket[] getBucket() {
        return buckets;
    }

    public void setBucket(Bucket[] buckets) {
        this.buckets = buckets;
    }

    public DumpCase getParent() {
        return parent;
    }

    public void setParent(DumpCase parent) {
        this.parent = parent;
    }

}

Bucket 类：

package cn.hncu.oil.common;

public class Bucket {//桶的容量和现在装的油的多少
    int now;
    int max;

    public Bucket(int max,int now) {
        this.max=max;
        this.now=now;
    }

    public void in(int n){
         now+=n;
    }

    public void out(int n){
        now-=n;
    }

    public int getNow() {
        return now;
    }

    public int getMax() {
        return max;
    }

    public int canIn(){
        return max-now;
    }

    public int canOut(){
        return now;
    }

    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result + max;
        result = prime * result + now;
        return result;
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj)
            return true;
        if (obj == null)
            return false;
        if (getClass() != obj.getClass())
            return false;
        Bucket other = (Bucket) obj;
        if (max != other.max)
            return false;
        if (now != other.now)
            return false;
        return true;
    }

}

Myset 类：

package cn.hncu.oil.common;

public class Myset {
    private Object[] objs = new Object[0];

    public boolean contains(Object obj){
        for(Object objtemp:objs){
            if(objtemp.equals(obj)){
                return true;
            }
        }
        return false;
    }

    public boolean add(Object obj){
        if(contains(obj)){
            return false;
        }
        Object[] objstemp = new Object[objs.length+1];
        System.arraycopy(objs, 0, objstemp, 0, objs.length);
        objstemp[objs.length]=obj;
        objs = objstemp;
        return true;
    }

    public Object[] getAll(){
        return objs;
    }

    public int Size(){
        return objs.length;
    }

}