动态规划之背包问题及输出背包具体方案

参考：https://blog.csdn.net/qq_27139155/article/details/79727991

#include <bits/stdc++.h>
using namespace std;
const int N=20;
int n,b;
int w[N],v[N],dp[N][N];//dp[i][j]表示容量为j，有i种物品时的最大价值
void dpp()
{
    for (int i=0;i<=b;i++)//物品种数为0时
    {
        dp[0][i]=0;
    }
    for (int i=0;i<=n;i++)//容量为0时
    {
        dp[i][0]=0;
    }
    int ans=0,last=0,mi,mj;//mi，mj标记最大值下标
    for (int i=1;i<=n;i++)
    {
        for (int j=1;j<=b;j++)
        {
            dp[i][j]=dp[i-1][j];
            if (w[i]<=j)
            {
                dp[i][j]=max(dp[i-1][j-w[i]]+v[i],dp[i-1][j]);//是否放入第i种物品
                ans=max(ans,dp[i][j]);
                mi=i;
                mj=j;
            }
        }
    }
    cout<<"总价值："<<endl;
    cout<<ans<<endl;
    stack<int> sa;
    for (int i=mi,j=mj;i>0;i--)//输出放入方案
    {
        if (dp[i][j]==dp[i-1][j-w[i]]+v[i])
        {
            sa.push(i);
            j=j-w[i];
        }
    }
    while (!sa.empty())
    {
        cout<<"放入第"<<sa.top()<<"件物品"<<endl;
        sa.pop();
    }
}
int main ()
{
//    freopen("in.txt","r",stdin);
    cout<<"input the number of goods:
";
    cin>>n;
    cout<<"input the weight of every goods:
";
    for (int i=1;i<=n;i++)
    {
        cin>>w[i];
    }
    cout<<"input the value of every goods:
";
    for (int i=1;i<=n;i++)
    {
        cin>>v[i];
    }
    cout<<"input the capacity of bag:
";
    cin>>b;
    dpp();

    return 0;
}