二维

/*
f[i][j] = max(f[i - 1][j], f[i - 1][j - v[i][k]] +  w[i][k])

*/
#include <iostream>
#include <algorithm>

using namespace std;

const int N = 110;

int n, m;
int v[N][N], w[N][N],s[N];
int f[N][N];

int main()
{
    cin >> n >> m;
    for (int  i = 1; i <= n; i ++ )
    {
        cin >> s[i];
        for (int j = 0; j < s[i]; j ++ )
        {
            cin >> v[i][j] >> w[i][j];
        }
    }

    for (int i = 1; i <= n; i ++ )
        for (int j = 0; j <= m; j ++ )
        {
            f[i][j] = f[i - 1][j];//第i组物品一个都不选
            for (int k = 0; k < s[i]; k ++ )
                if (j >= v[i][k]) f[i][j] = max(f[i][j], f[i - 1][j - v[i][k]] +  w[i][k]);
        }


    cout << f[n][m] << endl;
}

优化f[m]

/*
f[i][j] = max(f[i - 1][j], f[i - 1][j - v[i][k]] +  w[i][k])

*/
#include <iostream>
#include <algorithm>

using namespace std;

const int N = 110;

int n, m;
int v[N][N], w[N][N],s[N];
int f[N];

int main()
{
    cin >> n >> m;
    for (int  i = 1; i <= n; i ++ )
    {
        cin >> s[i];
        for (int j = 0; j < s[i]; j ++ )
        {
            cin >> v[i][j] >> w[i][j];
        }
    }

    for (int i = 1; i <= n; i ++ )
        for (int j = m; j >= 0; j -- )
            for (int k = 0; k < s[i]; k ++ )
                if (j >= v[i][k]) f[j] = max(f[j], f[j - v[i][k]] +  w[i][k]);



    cout << f[m] << endl;
}

彻底一维

#include <iostream>
#include <algorithm>

using namespace std;

const int N = 110;

int n, m;
int v[N], w[N],s;
int f[N];

int main()
{
    cin >> n >> m;
    for (int  i = 1; i <= n; i ++ )
    {
        cin >> s;
        for (int j = 0; j < s; j ++ )  cin >> v[j] >> w[j];

        for (int j = m; j >= 0; j -- )
            for (int k = 0; k < s; k ++ )
                if (j >= v[k]) f[j] = max(f[j], f[j - v[k]] +  w[k]);
    }
    cout << f[m] << endl;
}