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;    }}