Submission #1114492

#	Time	Username	Problem	Language	Result	Execution time	Memory
1114492		eysbutno	Crocodile's Underground City (IOI11_crocodile)	C++17	100 / 100	299 ms	62628 KiB

crocodile

#include <bits/stdc++.h>
using namespace std;

using ll = long long;

int travel_plan(int n, int m, int r[][2], 
                int l[], int k, int p[]) {
    vector<vector<array<int, 2>>> adj(n);
    for (int i = 0; i < m; i++) {
        adj[r[i][0]].push_back({r[i][1], l[i]});
        adj[r[i][1]].push_back({r[i][0], l[i]});
    }

    // we use 1e9 instead of INT_MAX to prevent overflow
    const array<int, 2> DEF = {(int) 1e9, (int) 1e9};
    vector<array<int, 2>> dist(n, DEF);
    priority_queue<array<int, 2>> pq;
    for (int i = 0; i < k; i++) {
        pq.push({0, p[i]});
        dist[p[i]] = {0, 0};
    }

    while (!pq.empty()) {
        auto [time, at] = pq.top();
        pq.pop();
        time *= -1; // undoing the negative number trick
        if (dist[at][1] < time) { continue; }
        for (const auto [nxt, weight] : adj[at]) {
            if (time + weight < dist[nxt][0]) {
                if (dist[nxt][0] < dist[nxt][1]) {
                    pq.push({-dist[nxt][0], nxt});
                }
                dist[nxt][1] = dist[nxt][0];
                dist[nxt][0] = time + weight;
            } else if (time + weight < dist[nxt][1]) {
                dist[nxt][1] = time + weight;
                pq.push({-dist[nxt][1], nxt});
            }
        }
    }
    return dist[0][1];
}

• Subtask 1: 46 / 46
• Subtask 2: 43 / 43
• Subtask 3: 11 / 11