0/1 knapsack

#include <bits/stdc++.h>

using namespace std;
typedef long long ll;

int cost[100][100];

int knapsack(int n, int W, int wm[], int vm[])
{
    for(int i=0; i<=W; i++)
        cost[0][i] = 0;

    for(int i=0; i<=n; i++)
        cost[i][0] = 0;

    for(int i=1; i<=n; i++)
    {
        for(int j=1; j<=W; j++)
        {
            if(wm[i] > j)
                cost[i][j] = cost[i-1][j];
            else
            {
                if (vm[i]+cost[i-1][j-wm[i]] > cost[i-1][j])
                    cost[i][j] = vm[i] + cost[i-1][j-wm[i]];
                else
                    cost[i][j] = cost[i-1][j];
            }
        }
    }
    return cost[n][W];
}

void items(int n, int W, int wm[])
{
    int i = n;
    int j = W;

    while (i > 0 && j > 0)
    {
        if(cost[i][j] != cost[i-1][j])
        {
            printf("%d\n",i);
            j-=wm[i];
            i--;
        }
        else
            i--;
    }
}

int main()
{
    #ifndef ONLINE_JUDGE
        freopen("input.txt", "r", stdin);
        freopen("output.txt", "w", stdout);
    #endif

    int n;
    cin >> n;
    int wm[n+2],vm[n+2];

    wm[0]=0, vm[0]=0;
    for(int i=1;i<=n;i++)
        cin >> wm[i] >> vm[i];

    cout << knapsack(n, 50, wm, vm) << endl;
    items(n, 50, wm);


    return 0;
}