Submission #1107540

#	Time	Username	Problem	Language	Result	Execution time	Memory
1107540		yanndev	Cyberland (APIO23_cyberland)	C++17	100 / 100	115 ms	66436 KiB

cyberland

#include "cyberland.h"
#include <bits/stdc++.h>
#define fi first
#define se second
#define ll long long
using namespace std;

vector<pair<int, int>> adj[100042];
bool vis[100042];
double dist[100042][71];
double pows[128];

void initDfs(int node, int H) {
    vis[node] = true;
    for (auto& x: adj[node])
        if (x.fi != H && !vis[x.fi])
            initDfs(x.fi, H);
}

double solve(int N, int M, int K, int H, vector<int> x, vector<int> y, vector<int> c, vector<int> arr) {
    K = min(K, 70);
    
    for (int i = 0; i < N; i++)
        adj[i].clear();

    
    pows[0] = 1;
    for (int i = 1; i <= K + 1; i++)
        pows[i] = pows[i - 1] / (double)2;

    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]});
    }

    for (int i = 0; i < N; i++)
        for (int j = 0; j <= K; j++)
            dist[i][j] = 1e18;

    for (int i = 0; i < N; i++)
        vis[i] = false;
        
    initDfs(0, H);

    priority_queue<tuple<double, int, int>> nxt {};

    arr[0] = 0;
    /*for (int i = 0; i < N; i++) {
        if (vis[i] && arr[i] == 0) {
            dist[i][0] = 0;
            nxt.push({0, 0, i});
        }
    }*/
    
    nxt.push({0, 0, H});
    dist[H][0] = 0;

    while (!nxt.empty()) {
        auto [dst, op2, at] = nxt.top();
        nxt.pop();
        dst *= -1;

        if (arr[at] == 0)
            return dst;

        if (dist[at][op2] == dst) {
            for (auto& x: adj[at]) {
                // no divide
                if (!vis[x.fi])
                    continue;
                
                double nxtDst = dst + (double)x.se * pows[op2];
                if (nxtDst < dist[x.fi][op2]) {
                    dist[x.fi][op2] = nxtDst;
                    nxt.push(make_tuple(-nxtDst, op2, x.fi));
                }

                // use divide
                nxtDst = dst + (double)x.se * pows[op2 + 1];
                if (arr[at] == 2 && op2 < K && nxtDst < dist[x.fi][op2 + 1]) {
                    dist[x.fi][op2 + 1] = nxtDst;
                    nxt.push(make_tuple(-nxtDst, op2 + 1, x.fi));   
                }
            }
        }
    }
    
    return -1;
}

• 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