Submission #751876

#	Time	Username	Problem	Language	Result	Execution time	Memory
751876		aryan12	Cyberland (APIO23_cyberland)	C++17	97 / 100	3042 ms	95424 KiB

cyberland

#include "cyberland.h"
#include <bits/stdc++.h>
#include <vector>
// #define int long long
using namespace std;

const int N = 1e5 + 1, K = 70;
double dist[K][N];
vector<pair<int, double> > 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(int32_t n, int32_t m, int32_t k, int32_t h, 
    vector<int32_t> x, vector<int32_t> y, vector<int32_t> c, 
    vector<int32_t> arr) 
{
    H = h;
    k = min(k, 69);
    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[j][i] = 1e18;
        }
    }
    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, pair<int, int> > > pq;
    for(int i = 0; i < n; i++)
    {
        // cout << "source[i] = " << source[i] << "\n";
        if(source[i])
        {
            pq.push({0, {i, 0}});
            dist[0][i] = 0;
        }
    }
    while(!pq.empty())
    {
        auto [dis, p] = pq.top();
        auto [node, cur_k] = p;
        pq.pop();
        dis = -dis;
        if(dist[cur_k][node] < dis || node == h)
        {
            continue;
        }
        for(auto [to, wt]: g[node])
        {
            if(a[to] == 0) continue;
            if(dist[cur_k][to] > dist[cur_k][node] + wt)
            {
                dist[cur_k][to] = dist[cur_k][node] + wt;
                pq.push({-dist[cur_k][to], {to, cur_k}});
            }
            if(a[to] == 1 || cur_k == k) continue;
            if(dist[cur_k + 1][to] > (dist[cur_k][node] + wt) / 2.0)
            {
                dist[cur_k + 1][to] = (dist[cur_k][node] + wt) / 2.0;
                pq.push({-dist[cur_k + 1][to], {to, cur_k + 1}});
            }
        }
    }
    double ans = 1e18;
    // for(int i = 0; i < n; i++)
    // {
    //     for(int j = 0; j <= k; j++)
    //     {
    //         cout << "dist[" << i << "][" << j << "] = " << dist[i][j] << "\n";
    //     }
    // }
    for(int i = 0; i <= k; i++)
    {
        ans = min(ans, dist[i][h]);
    }
    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