73: luogu 2014 树形dp

#include <bits/stdc++.h>

using namespace std;

#define Rep(i, a, b) for(int i = a; i <= b; i ++)

const int N = 305;

int fa[N];
vector <int> G[N];
int n, q;
int w[N];
int f[N][N];

void Dfs(int u) {
       int S = G[u].size();
    Rep(i, 0, S - 1) {
        int v = G[u][i];
        Dfs(v);
        for(int j = q + 1; j >= 1; j --) {
            for(int k = 0; k < j; k ++) {
                f[u][j] = max(f[u][j], f[v][k] + f[u][j - k]);
            }
        }
    }
}

int main() {
    cin >> n >> q;
    Rep(i, 1, n) {
        cin >> fa[i] >> w[i];
        f[i][1] = w[i];
        G[fa[i]].push_back(i);
    }
    Dfs(0);
    cout << f[0][q + 1];
    
    return 0;
}