C++实现动态规划算法之解决0-1背包问题

c++实现动态规划算法解决0-1背包问题

Main.cpp

//============================================================================
// Name        : Knapsack.cpp
// Author      : 
// Version     : 1.0
// Copyright   : Your copyright notice
// Description : 0-1背包算法问题
//============================================================================

#include <iostream>
#include<cstdlib>
#include"Knapsack.h"
#include<fstream>
#include <string>
using namespace std;


const char up='|';
const char left='-';
const char least='\\';
int** result;	//结果列表

int *weight;	//物品重量数组
int *value;		//价值数组

void fileInit(int &n,int &max)//
{
	ifstream in("input.txt");		//read file
	if(!in){cout<<"file is not exist!";return;}
	int num;
	int maxWeight;
	in>>num;
	in>>maxWeight;
	cout<<endl<<"物品数量："<<num<<endl<<"最大重量："<<maxWeight<<endl;

	weight=new int[num];
	value=new int[num];
	cout<<"重量数组：\t";
	for(int i=0;i<num;i++){in>>weight[i];cout<<setw(5)<<weight[i];}
	cout<<endl;
	cout<<"价值数组：\t";
	for(int i=0;i<num;i++){in>>value[i];cout<<setw(5)<<value[i];}
	cout<<endl;
	n=num;
	max=maxWeight;
	in.close();
}
int main() {
	cout << "0-1背包问题演示" << endl<<"从文件input.txt中初始化数据"; // prints Title
	int number=0;		//物品数量
	int maxWeight=0;	//背包最大重量
	fileInit(number,maxWeight);
	if(number==0){return 0;}
	result=new int *[number+1];
	for(int i = 0;i <= number;i++)
	{
	  result[i]=new int[maxWeight+1];
	}

	//int* location;		//最优解集合
	inItResult(result,number+1,maxWeight+1);	//init the result
	cout<<"the init table is:"<<endl;
	print(result,number+1,maxWeight+1);
	cout<<"the result table is:"<<endl;
	myKnapsack(value,weight,maxWeight,number,result);
	print(result,number+1,maxWeight+1);			//打印结果表格
	cout<<endl<<"最大值为："<<result[number][maxWeight]<<endl;
	system("pause");
	return 0;
}

Knapsack.h

#include<iostream>
#include<cstring>
#include<iomanip>
using namespace std;


//打印结果矩阵
template<class Type>
void print(Type** m,int n,int c)
{
	for(int i=0;i<n;i++)
	{
		for(int j=0;j<c;j++)
		{
			cout<<setw(5)<<m[i][j];
		}
		cout<<endl;
	}
}

//初始化结果矩阵
template<class Type>
void inItResult(Type** result,int n,int c)
{
	for(int i=0;i<n;i++)
		{
			for(int j=0;j<c;j++)
			{
				result[i][j]=0;
			}

		}
}

//动态规划算法
template<class Type>
void myKnapsack(Type *v,int* w,int c,int n,Type** m)
{
	for(int i=1;i<n+1;i++){
		for(int j=1;j<c+1;j++)
		{
			if(w[i-1]<=j){
				if(v[i-1]+m[i-1][j-w[i-1]]<m[i-1][j])
					m[i][j]=m[i-1][j];
				else m[i][j]=v[i-1]+m[i-1][j-w[i-1]];
			}else{
				m[i][j]=m[i-1][j];
			}
		}
	}

}