分组背包原理

int n, m;
int f[N];
int v[N][N], w[N][N], s[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 (v[i][k] <= j)f[j] = max(f[j], f[j - v[i][k]] + w[i][k]);
      }
    }
  }