Submission #976020

#	Time	Username	Problem	Language	Result	Execution time	Memory
976020		nnin	Cyberland (APIO23_cyberland)	C++17	68 / 100	3041 ms	15384 KiB

cyberland

#include "cyberland.h"
#include <bits/stdc++.h>
using namespace std;
#define pid pair<int,double>
#define f first
#define s second
#define A pair<double, int>

vector<pid> adj[100005];
bool reach[100005];
int HH, N;

void dfs(int u) {
    reach[u] = 1;
    if(u==HH) return;
    for(auto [v, w]:adj[u]) {
        if(!reach[v]) dfs(v);
    }
}

double mindis[100005];

void dij(vector<int> &arr) {
    priority_queue<A, vector<A>, greater<A>> pq;
    for(int i=0;i<N;i++) {
        if(reach[i] && mindis[i]<1e18) pq.push({mindis[i], i});
    }
    while(!pq.empty()) {
        auto [dis, u] = pq.top();
        pq.pop();
        if(u==HH || mindis[u]!=dis) continue;
        for(auto [v, w]:adj[u]) {
            if(reach[v] && mindis[v]>dis+w) {
                mindis[v] = dis+w;
                pq.push({mindis[v], v});
            }
        }
    }
    vector<pid> tmp;
    for(int u=0;u<N;u++) {
        double mn = mindis[u];
        if(reach[u] && arr[u]==2) {
            for(auto [v, w]:adj[u]) {
                if(reach[v] && v!=HH) mn = min(mn, (mindis[v]+w)/2.0);
            }
        }
        if(mn<mindis[u]) tmp.push_back({u, mn});
    }
    for(auto [u, dis]:tmp) {
        mindis[u] = min(mindis[u], dis);
    }
}

double solve(int NN, int M, int K, int H, vector<int> x, vector<int> y, vector<int> c, vector<int> arr) {
    HH = H; N = NN;
    for(int i=0;i<N;i++) {
        adj[i].clear();
        reach[i] = 0;
        mindis[i] = 1e18;
    }
    for(int i=0;i<M;i++) {
        adj[x[i]].push_back({y[i], (double)c[i]});
        adj[y[i]].push_back({x[i], (double)c[i]});
    }
    dfs(0);
    if(!reach[H]) return -1;
    mindis[0] = 0;
    for(int i=1;i<N;i++) {
        if(reach[i] && arr[i]==0) {
            mindis[i] = 0;
        }
    }
    for(int i=0;i<K;i++) dij(arr);
    return mindis[H];
}

• 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: 0 / 29
• Subtask 8: 0 / 3