Hackerearth problem -The Chocolate Boy

#include <bits/stdc++.h>
#define vi vector<int>
#define ll long long
using namespace std;
ll dp[1002][1002];
vector<ll> v1,v2;
ll knapsack(int n,int m,int flag)
{
  if(m<0)
   return INT_MIN;
  if(n==0)
   return 0;
  if(dp[n][m]!=-1)
   return dp[n][m];

  if(flag==0)
    return dp[n][m]=max(v2[n-1]+knapsack(n-1,m-v1[n-1],0),max(v2[n-1]+knapsack(n-1,m-v1[n-1]/2,1),knapsack(n-1,m,0)));
  else
    return dp[n][m]=max(v2[n-1]+knapsack(n-1,m-v1[n-1],1),knapsack(n-1,m,1));

}
int main()
{
    int n,m;
    cin>>n>>m;
    string s[n];
    char d[n];int a[n],b[n];
    for(int i=0;i<n;i++)
     cin>>s[i]>>d[i]>>a[i]>>b[i];
    for(int i=0;i<=n;i++)
    {
        for(int j=0;j<=m;j++)
         dp[i][j]=-1;
    }
    for(int i=0;i<n;i++)
    {
      if(d[i]=='S')
      {
        v1.push_back(a[i]);
        v2.push_back(b[i]);
        }
    }
    int n1=v1.size();
    cout<<knapsack(n1,m,0);
    return 0;
}