Submission #1241693

#	Time	Username	Problem	Language	Result	Execution time	Memory
1241693		bangan	Closing Time (IOI23_closing)	C++20	0 / 100	1098 ms	42104 KiB

closing

#include "closing.h"
#include <bits/stdc++.h>
using namespace std;

#define pb push_back
#define eb emplace_back
#define ALL(a) a.begin(), a.end()

#define ll long long
#define MP make_pair
#define pii pair<int, int>

const ll INF = 1ll << 50;
// const int MXN = 1<<20;

int none(int N, int X, int Y, long long K, std::vector<int> U, std::vector<int> V, std::vector<int> W) {
    vector<vector<pii>> adj(N);
    for (int i=0; i < N-1; i++) {
        adj[V[i]].eb(U[i], W[i]);
        adj[U[i]].eb(V[i], W[i]);
    }

    vector<bool> done(N);
    vector<ll> d(N, INF);
    d[X] = d[Y] = 0;
    priority_queue<pii, vector<pii>, greater<pii>> pq;
    pq.emplace(0, X);
    pq.emplace(0, Y);
    int ans = 0;

    while (!pq.empty()) {
        auto [_, v] = pq.top();
        pq.pop();
        if (done[v]) continue;
        done[v] = true;
        if (d[v] <= K) {
            ans++;
            K -= d[v];
        }
        for (auto [u, w] : adj[v]) if (d[v]+w < d[u]) {
            d[u] = d[v]+w;
            pq.push(MP(d[u], u));
        }
    }
    return ans;
}

int max_score(int N, int X, int Y, long long K, std::vector<int> U, std::vector<int> V, std::vector<int> W) {
    vector<vector<pii>> adj(N);
    for (int i=0; i < N-1; i++) {
        adj[V[i]].eb(U[i], W[i]);
        adj[U[i]].eb(V[i], W[i]);
    }

    vector<array<ll, 2>> f(N);
    auto dfs = [&](auto self, int v, int p, int c) -> void {
        for (auto [u, w] : adj[v]) if (u!=p) {
            f[u][c] = f[v][c] + w;
            self(self, u, v, c);
        }
    };
    dfs(dfs, X, X, 0);
    dfs(dfs, Y, Y, 1);

    vector<int> save_by_x(N), save_by_y(N);
    iota(ALL(save_by_x), 0);
    iota(ALL(save_by_y), 0);
    sort(ALL(save_by_x), [&](int v, int u) {
        return f[v][0]>f[u][0];
    });
    sort(ALL(save_by_y), [&](int v, int u) {
        return f[v][1]>f[u][1];
    });

    vector<int> save_c(N, -1);
    {
        vector<int> stk;
        auto DFS = [&](auto self, int v, int p) -> void {
            stk.pb(v);
            if (v == Y) for (int it : stk) save_c[it] = min(f[it][0], f[it][1]);
            for (auto [u, w] : adj[v]) if (u!=p) {
                self(self, u, v);
            }
            stk.pop_back();
        };
        DFS(DFS, X, X);
    }

    int ans = none(N, X, Y, K, U, V, W);
    auto check = [&](int m, int l) {
        vector<int> all;
        vector<int> c = save_c;
        auto add = [&](auto self, int v, int fa) -> void {
            if (c[v] != -1) all.pb(v);
            for (auto [u, w] : adj[v]) if (c[u] != -1 && u!=fa) self(self, u, v);
        };

        vector<int> P;
        for (int v=0; v<N; v++) if (c[v] != -1) P.pb(v);
        sort(ALL(P), [&](int v, int u) {
            return max(f[v][0],f[v][1]) > max(f[u][0],f[u][1]);
        });

        if (P.size()<l) return -1;

        ll k = K;
        for (int it : c) if (it != -1) k -= it;
        for (int _=0; _<l; _++) {
            int v = P.back();
            P.pop_back();
            if (c[v] != -1) k += c[v];
            c[v] = max(f[v][0], f[v][1]);
            k -= c[v];
            add(add, v, v);
        }
        sort(ALL(all), [&](int v, int u) {
        return max(f[v][0],f[v][1]) > max(f[u][0],f[u][1]);
        });

        if (all.size()<m) return -1;

        for (int _=0; _<m; _++) {
            int v = all.back();
            all.pop_back();
            if (c[v] != -1) k += c[v];
            c[v] = max(f[v][0], f[v][1]);
            k -= c[v];
        }
        if (k<0) return -1;

        int res = 0;
        vector<int> by_x = save_by_x;
        vector<int> by_y = save_by_y;
        while (!by_x.empty() || !by_y.empty()) {
            bool flg = false;
            if (!by_x.empty() && !by_y.empty()) {
                int v = by_x.back();
                int u = by_y.back();
                if (f[v][0]<f[u][1]) flg = true;
            }
            if (by_y.empty() || flg) {
                int v = by_x.back();
                by_x.pop_back();
                if (f[v][1]<=f[v][0] && c[v] < f[v][0]) continue;
                if (c[v] != -1 || f[v][0]<=k) {
                    res++;
                    if (c[v] == -1) k -= f[v][0];
                }
            }
            else {
                int v = by_y.back();
                by_y.pop_back();
                if (f[v][0]<=f[v][1] && c[v] < f[v][1]) continue;
                if (c[v] != -1 || f[v][1]<=k) {
                    res++;
                    if (c[v] == -1) k -= f[v][1];
                }
            }
        }
        return res;
    };
    // for (int k=MXN; 1<=k; k>>=1) if (m+k <= N && check(m+k) != -1) m += k;
    // return max(ans, check(m));
    for (int m=0; m <= N; m++) for (int l=1; l <= N; l++) ans = max(ans, check(m, l));
    return ans;
}

• Subtask 0: 0 / 0
• Subtask 1: 0 / 8
• Subtask 2: 0 / 9
• Subtask 3: 0 / 12
• Subtask 4: 0 / 14
• Subtask 5: 0 / 9
• Subtask 6: 0 / 11
• Subtask 7: 0 / 10
• Subtask 8: 0 / 10
• Subtask 9: 0 / 17