Submission #749263

#	Time	Username	Problem	Language	Result	Execution time	Memory
749263		dxz05	Cyberland (APIO23_cyberland)	C++17	100 / 100	2048 ms	80808 KiB

cyberland

#pragma GCC optimize("Ofast,O1,O2,O3,unroll-loops")
#pragma GCC target("avx,avx2")

#include "cyberland.h"
#include <bits/stdc++.h>

using namespace std;

vector<vector<pair<int, double>>> g;

vector<bool> used;
vector<int> zeros;
void dfs(int v, const vector<int> &arr){
    used[v] = true;
    if (arr[v] == 0 || v == 0) zeros.push_back(v);

    for (auto [u, w] : g[v]){
        if (!used[u]){
            dfs(u, arr);
        }
    }
}

double solve(int N, int M, int K, int H, std::vector<int> x, std::vector<int> y, std::vector<int> c, std::vector<int> arr) {
    K = min(K, 70);

    g.clear();
    g.resize(N);

    for (int i = 0; i < M; i++) {
        if (y[i] != H) g[x[i]].emplace_back(y[i], c[i]);
        if (x[i] != H) g[y[i]].emplace_back(x[i], c[i]);
    }

    zeros.clear();
    used.assign(N, false);

    dfs(0, arr);

    const double INF = 2e15;

    vector<vector<double>> dp(N, vector<double>(K + 1, INF));
    for (int v : zeros){
        dp[v].assign(K + 1, 0);
    }

    double ans = INF;

    for (int k = 0; k <= K; k++) {
        if (k > 0) {
            for (int i = 0; i < N; i++) {
                if (dp[i][k - 1] == INF) continue;
                dp[i][k] = min(dp[i][k], dp[i][k - 1]);

                if (arr[i] == 0) {
                    dp[i][k] = 0;
                }
            }
        }

        priority_queue<pair<double, int>> pq;
        for (int i = 0; i < N; i++) {
            if (dp[i][k] != INF) pq.emplace(-dp[i][k], i);
        }

        vector<bool> processed(N, false);

        while (!pq.empty()) {
            int v = pq.top().second;
            pq.pop();
            if (processed[v]) continue;
            processed[v] = true;

            for (auto [u, w]: g[v]) {
                double new_val = dp[v][k] + w;
                if (arr[u] == 0) new_val = 0;

                if (arr[u] == 2 && k < K) {
                    dp[u][k + 1] = min(dp[u][k + 1], (dp[v][k] + w) / 2);
                }

                if (dp[u][k] > new_val) {
                    dp[u][k] = new_val;
                    pq.emplace(-dp[u][k], u);
                }
            }

        }

        for (auto [v, w]: g[H]) {
            if (dp[v][k] == INF) continue;
            if (arr[H] == 0) return 0;

            ans = min(ans, dp[v][k] + w);
            if (k < K && arr[H] == 2) {
                ans = min(ans, (dp[v][k] + w) / 2);
            }
        }

    }

    if (ans == INF) return -1;

    return ans;
}

• Subtask 1: 5 / 5
• Subtask 2: 8 / 8
• Subtask 3: 13 / 13
• Subtask 4: 19 / 19
• Subtask 5: 7 / 7
• Subtask 6: 16 / 16
• Subtask 7: 29 / 29
• Subtask 8: 3 / 3