Submission #960946

#	Time	Username	Problem	Language	Result	Execution time	Memory
960946		Ghetto	Chase (CEOI17_chase)	C++17	30 / 100	732 ms	107080 KiB

chase

#include <bits/stdc++.h>
using namespace std;
using pii = pair<int, int>;
using lint = long long;
const int MAX_N = 1e5 + 5, MAX_K = 1e2 + 5;

int n, k;
lint val[MAX_N];
vector<int> adj[MAX_N], adj_ind[MAX_N]; // adj_ind[u][i] = ind of adj list u is for adj[u][i]

int par[MAX_N];
vector<int> children[MAX_N];
void init1() {
    for (int i = 1; i <= n; i++) children[i].push_back(0);
}
int child_ind[MAX_N];

int n_inds, ind[MAX_N], rev_ind[MAX_N];
void dfs(int u) {
    ind[u] = ++n_inds;
    rev_ind[ind[u]] = u;
    for (int v : adj[u]) {
        if (ind[v]) continue;
        par[v] = u;
        children[u].push_back(v);
        child_ind[v] = children[u].size() - 1;
        dfs(v);
    }
}

lint val_sum[MAX_N];

void precomp() {
    init1();

    dfs(1);

    for (int i = 1; i <= n; i++)
        for (int j : adj[i]) val_sum[i] += val[j];
}

lint dp1[MAX_N][MAX_K];
vector<lint> dp2[MAX_N][2];
void init2() {
    for (int i = 0; i <= n; i++)
        for (int c = 0; c <= 1; c++)
            dp2[i][c].resize(adj[i].size() + 2);
}

int main() {
    // freopen("chase.in", "r", stdin);

    cin >> n >> k;
    for (int i = 1; i <= n; i++) cin >> val[i];
    for (int i = 1; i < n; i++) {
        int u, v; cin >> u >> v;
        adj[u].push_back(v);
        adj[v].push_back(u);
    }

    precomp();

    for (int c = 1; c <= k; c++) {
        for (int i = n; i >= 1; i--) {
            int u = rev_ind[i];

            lint leave = 0;
            for (int v : children[u])
                if (v != 0) leave = max(leave, dp1[v][c]);

            lint take = 0; 
            for (int v : children[u])
                if (v != 0) take = max(take, dp1[v][c - 1]);
            take += val_sum[u] - val[par[u]];

            dp1[u][c] = max(take, leave);
        }
    }

    cout << dp1[1][k] << endl;

    // init2();
    // lint ans = 0;
    // for (int c = 0; c <= k; c++) {
    //     int opp_c = k - c;
    //     int p = c % 2, opp_p = (c + 1) % 2;
    //     for (int i = 1; i <= n; i++) {
    //         int u = rev_ind[i];

    //         multiset<lint> trans;
    //         trans.insert(0);
    //         for (int v : children[u]) trans.insert(dp1[v][opp_c]); // Should have 0

    //         for (int j = 0; j < children[u].size(); j++) {
    //             if (c == 0) continue;
    //             int v = children[u][j];

    //             lint leave = dp2[par[u]][p][child_ind[u]];
    //             lint take = dp2[par[u]][opp_p][child_ind[u]] + val_sum[u] - val[v];
    //             dp2[u][p][j] = max(take, leave);
    //         }
            
    //         for (int j = 0; j < children[u].size(); j++) {
    //             int v = children[u][j];
    //             trans.erase(trans.find(dp1[v][opp_c]));

    //             assert(trans.size());
    //             ans = max(ans, dp2[u][p][j] + *trans.rbegin());

    //             trans.insert(dp1[v][opp_c]);
    //         }
    //     }
    // }
    // cout << ans << '\n';
    
}

• Subtask 1: 0 / 20
• Subtask 2: 0 / 20
• Subtask 3: 30 / 30
• Subtask 4: 0 / 30