股票盈利问题(Java)——分治法(Maximum-subarray)_java分治法对股票实现“低买高卖”的收益最大化,写出相应的程序,-优快云博客

本文链接：https://blog.youkuaiyun.com/qq_37486501/article/details/83000226

本文介绍了一种使用分治法解决最大子数组问题的算法实现，通过递归分解数组并寻找最大子数组的策略，实现了高效的最大利润计算。代码支持整型和浮点型数据输入，适用于股票交易等场景。

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暴力法解此题:https://blog.youkuaiyun.com/qq_37486501/article/details/83000154

题目

在这里插入图片描述

注意:
1.本题采用txt文件读入,屏幕输出;
如果需要屏幕读入屏幕输出,可以留言或者自己改代码~
2.下面分int类型和double类型的数据读入,请选择适合自己的…
分治法(Maximum-subarray)代码如下:
要求(输入数据为int类型)

import java.io.BufferedReader;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
class Pro{
	private int i=0;//买入股票下标
	private int j=0;//卖出股票下标
	private int sum=0;//所加和
	private int k=0;
	public int getI() {
		return i;
	}
	public void setI(int i) {
		this.i = i;
	}
	public int getJ() {
		return j;
	}
	public void setJ(int j) {
		this.j = j;
	}
	public int getSum() {
		return sum;
	}
	public void setSum(int k) {
		this.sum =this.sum+k;
	}	
}

public class Lyx {
	
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		long startTime = System.currentTimeMillis();
		try {
		FileReader in = new FileReader("input.txt");
		BufferedReader inin=new BufferedReader(in);//读入文件
		 	try {
				 String str;   
				 int i=0;
				 int sum=Integer.parseInt(inin.readLine());
				 int[] datalist=new int[sum];
				while((str=inin.readLine())!=null)//每次读一行,注意双层括号
				 { 
				     datalist[i]=Integer.parseInt(str);
				     i++;
				 }
				int[] list=new int[sum];
				for(int m=1;m<sum;m++)
				{
					list[m]=datalist[m]-datalist[m-1];//list[ ]为股票( 后一天 - 前一天 )
				    //System.out.print(list[m]+" ");
				}		
				System.out.println("Maximum-subarray求解:");
	System.out.println("第"+(FindMaxSubarray(list,1,sum-1).getI()-1)+"日收盤買進第"+FindMaxSubarray(list,1,sum-1).getJ()+"日收盤賣出最高獲利為"+FindMaxSubarray(list,1,sum-1).getSum()+"元!");//求最大利润
		 	
		 	} catch (IOException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		} catch (FileNotFoundException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		
		//计算时间
		long endTime = System.currentTimeMillis();
	    System.out.print("执行时间： "+(endTime-startTime)+" ms");	
	}
	public static Pro FindMaxSubarray (int[] data, int low,int high) { 
		int mid;
		Pro leftsum=new Pro();
		Pro rightsum=new Pro();
		Pro midsum=new Pro();
		if(high==low)
		   { 
			Pro pro1=new Pro();
			pro1.setI(low);
			pro1.setJ(high);
			pro1.setSum(data[high]);
			}
		else
			{	mid = (low+high)/2; 
				leftsum=FindMaxSubarray(data,low,mid);
				rightsum=FindMaxSubarray(data,mid+1,high);
				midsum=FindMaxCrossingSubarray(data,low,mid,high);
			}
				if((leftsum.getSum()>=rightsum.getSum())&&(leftsum.getSum()>=midsum.getSum()))
				{
					return leftsum;
				}
				else if((rightsum.getSum()>=leftsum.getSum())&&(rightsum.getSum()>=midsum.getSum()))
				{
					return rightsum;
				}
				else if((midsum.getSum()>=leftsum.getSum())&&(midsum.getSum()>=rightsum.getSum()))
				{
					return midsum;
				}			
		return null;  
	}
	public static Pro FindMaxCrossingSubarray (int[] data, int low,int mid,int high) {
		//以中间开始,向左边求sum1的max,向右边求sum2的max,两个max相加
		//左侧
		Pro pro1=new Pro();
		int leftsum=-1000;
		int sum1=0;//左侧各项相加的和
		int maxleftid=0;//左侧max时的i值
		for(int i=mid;i>=low;i--)
		{
			sum1=sum1+data[i];
			if(sum1>leftsum)
			{
				leftsum=sum1;
				maxleftid=i;	
			}
		}
		pro1.setSum(leftsum);
		pro1.setI(maxleftid);
		//右侧
		int rightsum=-1000;
		int sum2=0;//右侧各项相加的和
		int maxrightid=0;//右侧max时的i值
		for(int i=mid+1;i<=high;i++)
		{
			sum2=sum2+data[i];
			if(sum2>rightsum)
			{
				rightsum=sum2;
				maxrightid=i;	
			}
		}
		pro1.setSum(rightsum);
		pro1.setJ(maxrightid);
		return pro1;
	}
}

分治法(Maximum-subarray)代码如下:
要求(输入数据为double类型)

 import java.io.BufferedReader;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
class Pro{
	private int i=0;//买入股票下标
	private int j=0;//卖出股票下标
	private double sum=0;//所加和
	private double k=0;
	public int getI() {
		return i;
	}
	public void setI(int i) {
		this.i = i;
	}
	public int getJ() {
		return j;
	}
	public void setJ(int j) {
		this.j = j;
	}
	public double getSum() {
		return sum;
	}
	public double setSum(double k) {
		return this.sum =this.sum+k;
	}	
}

public class Lyx {
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		long startTime = System.currentTimeMillis();
		try {
		FileReader in = new FileReader("input_2330.txt");
		BufferedReader inin=new BufferedReader(in);//读入文件
		 	try {
				 String str;   
				 int i=0;
				 int sum=Integer.parseInt(inin.readLine());
				 double[] datalist=new double[sum];
				while((str=inin.readLine())!=null)//每次读一行,注意双层括号
				 { 
				     datalist[i]=Double.parseDouble(str);
				     i++;
				 }
				double[] list=new double[sum];
				for(int m=1;m<sum;m++)
				{
					list[m]=datalist[m]-datalist[m-1];//list[ ]为股票( 后一天 - 前一天 )
				    //System.out.print(list[m]+" ");
				}			
				System.out.println("Maximum-subarray求解:");
	System.out.println("第"+(FindMaxSubarray(list,1,sum-1).getI()-1)+"日收盤買進第"+FindMaxSubarray(list,1,sum-1).getJ()+"日收盤賣出最高獲利為"+FindMaxSubarray(list,1,sum-1).getSum()+"元!");//求最大利润
		 	
		 	} catch (IOException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		} catch (FileNotFoundException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		
		//计算时间
		long endTime = System.currentTimeMillis();
	    System.out.print("执行时间： "+(endTime-startTime)+" ms");	
	}
	public static Pro FindMaxSubarray (double[] data, int low,int high) { 
		int mid;
		Pro leftsum=new Pro();
		Pro rightsum=new Pro();
		Pro midsum=new Pro();
		if(high==low)
		   { 
			Pro pro1=new Pro();
			pro1.setI(low);
			pro1.setJ(high);
			pro1.setSum(data[high]);
			}
		else
			{	mid = (low+high)/2; 
				leftsum=FindMaxSubarray(data,low,mid);
				rightsum=FindMaxSubarray(data,mid+1,high);
				midsum=FindMaxCrossingSubarray(data,low,mid,high);
			}
				if((leftsum.getSum()>=rightsum.getSum())&&(leftsum.getSum()>=midsum.getSum()))
				{
					return leftsum;
				}
				else if((rightsum.getSum()>=leftsum.getSum())&&(rightsum.getSum()>=midsum.getSum()))
				{
					return rightsum;
				}
				else if((midsum.getSum()>=leftsum.getSum())&&(midsum.getSum()>=rightsum.getSum()))
				{
					return midsum;
				}			
		return null;  
	}
	public static Pro FindMaxCrossingSubarray (double[] data, int low,int mid,int high) {
		//以中间开始,向左边求sum1的max,向右边求sum2的max,两个max相加
		//左侧
		Pro pro1=new Pro();
		double leftsum=-1000;
		double sum1=0;//左侧各项相加的和
		int maxleftid=0;//左侧max时的i值
		for(int i=mid;i>=low;i--)
		{
			sum1=sum1+data[i];
			if(sum1>leftsum)
			{
				leftsum=sum1;
				maxleftid=i;	
			}
		}
		pro1.setSum(leftsum);
		pro1.setI(maxleftid);
		//右侧
		double rightsum=-1000;
		double sum2=0;//右侧各项相加的和
		int maxrightid=0;//右侧max时的i值
		for(int i=mid+1;i<=high;i++)
		{
			sum2=sum2+data[i];
			if(sum2>rightsum)
			{
				rightsum=sum2;
				maxrightid=i;	
			}
		}
		pro1.setSum(rightsum);
		pro1.setJ(maxrightid);
		return pro1;
	}
}