knapsack

1#include<bits/stdc++.h>
2using namespace std;
3vector<pair<int,int> >a;
4//dp table is full of zeros
5int n,s,dp[1002][1002];
6void ini(){
7    for(int i=0;i<1002;i++)
8        for(int j=0;j<1002;j++)
9            dp[i][j]=-1;
10}
11int f(int x,int b){
12	//base solution
13	if(x>=n or b<=0)return 0;
14	//if we calculate this before, we just return the answer (value diferente of 0)
15	if(dp[x][b]!=-1)return dp[x][b];
16	//calculate de answer for x (position) and b(empty space in knapsack)
17	//we get max between take it or not and element, this gonna calculate all the
18	//posible combinations, with dp we won't calculate what is already calculated.
19	return dp[x][b]=max(f(x+1,b),b-a[x].second>=0?f(x+1,b-a[x].second)+a[x].first:INT_MIN);
20}
21int main(){
22	//fast scan and print
23	ios_base::sync_with_stdio(0);cin.tie(0);
24	//we obtain quantity of elements and size of knapsack
25	cin>>n>>s;
26	a.resize(n);
27	//we get value of elements
28	for(int i=0;i<n;i++)
29		cin>>a[i].first;
30	//we get size of elements
31	for(int i=0;i<n;i++)
32		cin>>a[i].second;
33	//initialize dp table
34	ini();
35	//print answer
36	cout<<f(0,s);
37	return 0;
38}
39