Submission #972682

#	Time	Username	Problem	Language	Result	Execution time	Memory
972682		TheSahib	Cyberland (APIO23_cyberland)	C++17	100 / 100	1780 ms	15028 KiB

cyberland

#include "cyberland.h"
#include <bits/stdc++.h>
 
using namespace std;
 
typedef long long ll;
 
const int MXN = 1e5 + 5;
 
int n, m, k, h;
vector<pair<int, double>> adj[MXN];
int arr[MXN];
double dist[MXN], ndist[MXN];
priority_queue<pair<double, int>, vector<pair<double, int>>, greater<pair<double, int>>> pq;
vector<int> nodes;
 
void dijk(int s, int F)
{
    for (int i = 0; i < n; i++) ndist[i] = -1;
    for (int &x : nodes) ndist[x] = 0;
    if (F)
    {
        for (int i = 0; i < n; i++) 
        {
            if (arr[i] != 2) continue;
            for (pair<int, double> &v : adj[i])
            {
                if (v.first == h) continue;
                if (dist[v.first] == -1) continue;
                if (ndist[i] == -1) ndist[i] = (dist[v.first] + v.second) / 2;
                else ndist[i] = min(ndist[i], (dist[v.first] + v.second) / 2);
            }
        }
    }
    for (int i = 0; i < n; i++)
    {
        if (dist[i] != -1 && ndist[i] != -1) pq.push({min(dist[i], ndist[i]), i});
        else if (ndist[i] != -1) pq.push({ndist[i], i});
        else if (dist[i] != -1) pq.push({dist[i], i});
        
    }
    while (!pq.empty())
    {
        pair<double, int> f = pq.top();
        pq.pop();
        if (ndist[f.second] > f.first) continue;
        if (f.second == h) continue;
        for (pair<int, double> &v : adj[f.second])
        {
            if (ndist[v.first] == -1) 
            {
                ndist[v.first] = f.first + v.second;
                pq.push({ndist[v.first], v.first});
            }
            else if (ndist[v.first] > f.first + v.second) 
            {
                ndist[v.first] = f.first + v.second;
                pq.push({ndist[v.first], v.first});
            }
        }
    }
}
 
double solve(int N, int M, int K, int H, vector<int> x, vector<int> y, vector<int> c, vector<int> ARR)
{
    n = N, m = M, k = K, h = H;
    k = min(k, 70);
    for (int i = 0; i < n; i++) adj[i].clear(), arr[i] = ARR[i], dist[i] = -1;
    nodes.clear();
    for (int i = 0; i < m; i++)
    {
        adj[x[i]].push_back({y[i], c[i]});
        adj[y[i]].push_back({x[i], c[i]});
    }
    vector<int> u(n, 0);
    queue<int> q;
    u[0] = 1, q.push(0);
    while (!q.empty())
    {
        int f = q.front();
        q.pop();
        if (f == h) continue;
        for (pair<int, double> &v : adj[f])
        {
            if (u[v.first]) continue;
            u[v.first] = 1, q.push(v.first);
        }
    }
    for (int i = 0; i < n; i++)
    {
        if (u[i] && (!i || arr[i] == 0)) 
        {
            dist[i] = 0;
            nodes.push_back(i);
        }
        else dist[i] = -1;
    }
    double res = -1;
    for (int i = 0; i <= k; i++)
    {
        dijk(0, i);
        for (int i = 0; i < n; i++) 
        {
            if (dist[i] == -1) dist[i] = ndist[i];
            else if (ndist[i] != -1) dist[i] = min(dist[i], ndist[i]);
        }
        if (dist[h] != -1) 
        {
            if (res == -1) res = dist[h];
            else res = min(res, dist[h]);
        }
    }
    return res;
}

• 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