dynamic programming (backpack problem)

I got the code in c++ for the backpack problem.

Code:

---

#include <iostream>
using namespace std;

int main()
{
    long long int B[1000],C[1000];
    int V[100],Z[100],N,M,q,i;
   
    cin>>N>>M;
   
    for(i=1;i<=M;i++) cin>>Z[i];

  for(i=1;i<=M;i++) cin>>V[i];
   
    B[0]=0;
    C[0]=0;

    for (q=1;q<=N;q++)
    {
        B[q]=0;
        C[q]=0;

    for(i=1;i<=M;i++)

    if (Z[i]<=q)

    if (B[q-Z[i]]+V[i]>B[q])
    {

    B[q]=B[q-Z[i]]+V[i];
    C[q]=i;

    }

}
    cout<<B[N]<<endl;
 
   
return 0;
}

---

Can somebody explain the suboptimal solutions, and how the problem is solved.

Thanks in advance.

+karma for the person who will help me.

I think you better ask in Algorithm forum.