第七周作业——背包问题

package homework;
import java.io.*;
import java.util.*;
public class Knapsack {
	  static int count=0;  //容量为15
	  static int allweight=0;
	  static int weight[]={0,0,0,0,0}; //物品的重量
	  static int value[]={0,0,0,0,0};	//物品的价值
	  static int result[]={-1,-1,-1,-1,-1};//初始化背包
	  
	public static void main(String[] args) {
	    String path = "C:\\Users\\orion\\Desktop\\Knapsack.txt";
	    ArrayList<Integer> list = read(path);
	    
	    for(int i=2,j=0;i<list.size();i=i+2,j++){
	      
	      weight[j]=list.get(i);
	    }
	    for(int i=3,j=0;i<list.size();i=i+2,j++){
	      
	      value[j]=list.get(i);
	    }
	    //控制台打印
	    Knapsack ks=new Knapsack();
	    System.out.println("总价值："+ks.Knapsacountk(list.get(1)-1,list.get(0)));
	    System.out.print("物品编号：");
	    ks.printNum();
	    System.out.println();
	    System.out.println("总重量："+allweight);
	    //写入txt
	    ks.writeFile(result);
	    
	  }


	  public void printNum(){
	    for(int i=0;i<result.length;i++)
	    {
	    	if(result[i]==1){
	    		System.out.print(i+1+",");
	    		allweight+=weight[i];
	    	}
	    }
	  }


	  
	  public  void writeFile(int[] list) {
	    File f = new File("C:\\Users\\orion\\Desktop\\KnapsackResult.txt");
	    FileOutputStream fou = null;
	    try {
	      fou = new FileOutputStream(f);
	      String s,a;
	      a=new String("物品编号\t物品重量\t物品价值\t\n");
	      for (int i = 0; i < list.length; i++) {
	    	  if(list[i]==1){
		        s = String.valueOf(list[i]);
		        a += i+1+"    \t" + weight[i] + "    \t"+value[i]+"    \t\n";
	    	  }
	        
	      }
	        fou.write(a.getBytes());
	        fou.close();
	    } catch (Exception e) {
	      e.printStackTrace();
	    }
	  }
	  
	  
	  
	  public int Knapsacountk(int n ,int count)
	  {
	    if(n==-1||count==0)
	      return 0;
	    int tmp1=Knapsacountk(n-1,count);
	    if(weight[n]>count)
	    {
	      result[n]=0;
	      return tmp1;
	    }
	    int tmp2=value[n]+Knapsacountk(n-1,count-weight[n]);
	    if(tmp1>tmp2)
	    {
	      result[n]=0;
	      return tmp1;
	    }
	    result[n]=1;
	    return tmp2;	
	  }
	  
	  
	  // 读取文件到Arraylist 数组
	      public static ArrayList read(String path) {
	        ArrayList<Integer> list = new ArrayList<Integer>();
	        BufferedReader input = null;
	        try {
	          FileReader in = new FileReader(path);
	          input = new BufferedReader(in);
	          String ss;
	            while ((ss = input.readLine()) != null) {
	              String[] s = (ss.split("  "));
	              for (int i = 0; i < s.length; i++) {
	            	  list.add(Integer.parseInt(s[i].trim())); 
	              }
	            }
	          in.close();
	          input.close();
	        } catch (Exception e) {
	          e.printStackTrace();
	        }


	        return list;
	      }


}