最优装载

Posted 2021-01-18 howbin

最优装载

贪心算法

一问题描述

二问题分析

三代码实现

 package loading;

import java.io.BufferedWriter;
import java.io.FileWriter;
import java.io.IOException;
import java.util.Arrays;
import java.util.Comparator;

public class bin
{

	public static void main(String[] args) throws IOException
	{
		    int []w= {0,30,10,60,40,50,20};    
		    int c=150;
		    element []ele=new element[w.length-1] ;
		    for(int i=1; i<w.length; i++)
		    {
		    	ele[i-1]=new element(w[i],i);
		    }
		    greedyLoading myGreedyLoading=new greedyLoading(ele, c);
	}

}
class element   //集装箱类
{
	int w;   //重量   
	int i;   //编号
	int x=0;   //是否上船
	public element(int w,int i)
	{
		this.w=w;
		this.i=i;
	}
}
class greedyLoading
{
	element []ele;
	int c;            //船的容量
	int opt=0;        //最优装载
	int rc;           //剩余载重量
    public greedyLoading(element []ele,int c) throws IOException
	{
		this.ele=ele;
		this.c=c;
		this.rc=c;
		GreedyLoading();
		display();
	}
    public void GreedyLoading()
    {
    	Arrays.sort(ele, new Comparator<element>(){
			//传入的时候由用户自己选
			@Override
			public int compare(element o1, element o2) {
				// TODO Auto-generated method stub
				int finsh1 = o1.w;
				int finsh2 = o2.w;
			    if (finsh1>finsh2)
			    {
			    	return 1;
			    }
			    else
			    {
			    	if (finsh1<finsh2)
				    {
				    	return -1;
				    }else 
				    {
				    	return 0;
				    }
			 
			    }
				
			}
		});
    	for(int i=0; i<ele.length; i++)
    	{
    		if(ele[i].w<=rc)
    		{
    			ele[i].x=1;  //安排
    			rc-=ele[i].w;
    			opt+=ele[i].w;
    		}
    		else 
    		{
    			break;
    		}
    	}
    }
    public void display() throws IOException
    {
    	BufferedWriter fout=new BufferedWriter(new FileWriter("out.txt"));
    	fout.write("c="+c);
		fout.newLine();
		fout.write("rc="+rc);
		fout.newLine();
		fout.write("opt="+opt);
		fout.newLine();
		for(int i=0; i<ele.length; i++)
		{
			fout.write("ele["+i+"]:");
			fout.newLine();
			fout.write("i:	"+ele[i].i);
			fout.newLine();
			fout.write("s:	"+ele[i].w);
			fout.newLine();
			fout.write("x:	"+ele[i].x);
			fout.newLine();
		    fout.write("+++++++++++++++++++");
		    fout.newLine();
		}
		fout.flush();
    }
}


enter code here

四运行结果

五总结收获

1.熟练贪心算法

六不足
1.手速太慢