简单背包问题（实际上是子集问题）

从一堆物品weight[1]，。。weight
中，从中选取若干件放入背包，使其重量恰好为s ，实际上对weight进行全排列，然后只要和为s，即可输出方案。

例如：

How many weight do you want to input..
6
Input 6 weight
3 4 6 5 7 2
Input the total Weight you want..
12
3+4+5 = 12
5+7 = 12
4+6+2 = 12
3+7+2 = 12
Press any key to continue

源程序：cpp文件：

#include "Knap.h"

void main()
{
vector<int>Weight;
int x;
int SUM;
int Count = 0;
cout<<"How many weight do you want to input.."<<endl;
cin>>Count;
cout<<"Input "<<Count<<" weight "<<endl;
for(int i = 0;i<Count;i++)
{
cin>>x;
Weight.push_back(x);
}
cout<<"Input the total Weight you want.."<<endl;
cin>>SUM;
Knap(Weight,Weight.size()-1,SUM);
}

头文件：Knap.h

#include<iostream>
#include<vector>
#include<string>
using namespace std;

void Delete(vector<int>&Test,int j)
{
vector<int> Temp;
for(int i = 0;i<j;i++)
{
Temp.push_back(Test[i]);
}
for(i = j+1;i<Test.size();i++)
{
Temp.push_back(Test[i]);
}
while(!Test.empty())
{
Test.pop_back();
}
Test = Temp;
}
int sum(vector<int> Weight)
{
int sum = 0;
for(int i = 0;i<Weight.size();i++)
{
sum += Weight[i];
}
return sum;
}
//递归算法
void Knap(vector<int> Weight,int n,int SUM)
{
if(n < 0)
{
if(sum(Weight) == SUM)
{
for(int i = 0;i<Weight.size()-1;i++)
{
cout<<Weight[i]<<"+";
}
cout<<Weight[Weight.size()-1]<<" = "<<SUM;
cout<<endl;
}
}
else
{
vector<int>Temp;
Temp = Weight;
Delete(Weight,n);
Knap(Weight,n-1,SUM);
Weight = Temp;
Knap(Weight,n-1,SUM);
}

}