Submission #751898

#	Time	Username	Problem	Language	Result	Execution time	Memory
751898		aryan12	Cyberland (APIO23_cyberland)	C++17	97 / 100	3065 ms	92496 KiB

cyberland

#include "cyberland.h"
#include <bits/stdc++.h>
using namespace std;
 
const int N = 1e5, K = 67;
double dist[N][K];
vector<pair<int, int> > g[N];
bool vis[N], source[N];
int a[N], H;
 
void dfs(int node)
{
    vis[node] = true;
    if(a[node] == 0)
    {
        source[node] = true;
    }
    if(node == H)
    {
        return;
    }
    for(auto [to, wt]: g[node])
    {
        if(!vis[to])
        {
            dfs(to);
        }
    }
}
 
double solve(int n, int m, int k, int h, 
    vector<int> x, vector<int> y, vector<int> c, 
    vector<int> arr) 
{
    H = h;
    k = min(k, 66);
    for(int i = 0; i <= n; i++)
    {
        source[i] = false;
        vis[i] = false;
        if(i != n) a[i] = arr[i];
        g[i].clear();
        for(int j = 0; j <= k; j++)
        {
            dist[i][j] = 1e14;
        }
    }
    for(int i = 0; i < m; i++)
    {
        g[x[i]].push_back({y[i], c[i]});
        g[y[i]].push_back({x[i], c[i]});
    }
    dfs(0);
    source[0] = true;
    if(!vis[H])
    {
        return -1;
    }
    priority_queue<pair<double, int> > pq;
    for(int i = 0; i < n; i++)
    {
        // cout << "source[i] = " << source[i] << "\n";
        if(source[i])
        {
            pq.push({0, i});
            dist[i][0] = 0;
        }
    }
    while(!pq.empty())
    {
        auto [dis, p] = pq.top();
        pq.pop();
        int cur_k = p / 100000, node = p % 100000;
        dis = -dis;
        if(dist[node][cur_k] < dis || node == h)
        {
            continue;
        }
        for(auto [to, wt]: g[node])
        {
            if(a[to] == 0) continue;
            double wt_d = wt;
            if(dist[to][cur_k] > dist[node][cur_k] + wt_d)
            {
                dist[to][cur_k] = dist[node][cur_k] + wt_d;
                pq.push({-dist[to][cur_k], to + 100000 * cur_k});
            }
            if(a[to] == 1 || cur_k == k) continue;
            if(dist[to][cur_k + 1] > (dist[node][cur_k] + wt_d) / 2.0)
            {
                dist[to][cur_k + 1] = (dist[node][cur_k] + wt_d) / 2.0;
                pq.push({-dist[to][cur_k + 1], to + 100000 * (cur_k + 1)});
            }
        }
    }
    // for(int i = 0; i < n; i++)
    // {
    //     for(int j = 0; j <= k; j++)
    //     {
    //         cout << "dist[" << i << "][" << j << "] = " << dist[i][j] << "\n";
    //     }
    // }
    double ans = dist[h][0];
    for(int i = 1; i <= k; i++)
    {
        ans = min(ans, dist[h][i]);
    }
    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: 0 / 3