Submission #995986

#	Time	Username	Problem	Language	Result	Execution time	Memory
995986		54skyxenon	Crocodile's Underground City (IOI11_crocodile)	C++17	100 / 100	1546 ms	125996 KiB

crocodile

// https://oj.uz/problem/view/IOI11_crocodile

// #define LOCAL_TESTING 1

/** Needed for linking!!! */

#ifndef LOCAL_TESTING
#include "crocodile.h"
#endif

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

#define ll long long
#define INF (ll)1e18

vector<map<int, int>> graph;
vector<bool> is_exit;
vector<set<int>> visited;

ll dijkstra() {
    vector<vector<ll>> dist(graph.size(), {INF, INF});
    priority_queue<pair<ll, ll>> pq;

    for (ll i = 0; i < graph.size(); i++) {
        if (is_exit[i]) {
            pq.push({0, i});
            dist[i][0] = dist[i][1] = 0;
        }
    }

    while (pq.size()) {
        auto [d, u] = pq.top();
        pq.pop();
        d = -d;

        if (d > dist[u][1]) {
            continue;
        }

        for (auto& [v, w] : graph[u]) {
            ll cost = w + d;

            if (cost < dist[v][0]) {
                if (dist[v][0] != dist[v][1] && dist[v][0] < INF) {
                    dist[v][1] = dist[v][0];
                    pq.push({-dist[v][1], v});
                }
                dist[v][0] = cost;
            }
            else if (cost < dist[v][1]) {
                dist[v][1] = cost;
                pq.push({-cost, v});
            }
        }
    }

    return dist[0][1];
}

int travel_plan(int N, int M, int R[][2], int L[], int K, int P[]) {
    graph.resize(N);
    is_exit.resize(N);
    visited.resize(N);

    for (int i = 0; i < M; i++) {
        graph[R[i][0]][R[i][1]] = graph[R[i][1]][R[i][0]] = L[i];
    }

    for (int i = 0; i < K; i++) {
        is_exit[P[i]] = true;
    }
        
    return dijkstra();
}

#ifdef LOCAL_TESTING

/**
 * 0 2
0 3
3 2
2 1
0 1
0 4
3 4

L=
4
3
2
10
100
7
9
P= 1
3
 */
int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);

    int n = 5;
    int m = 7;
    int k = 2;

    int r[7][2] = {
        {0, 2},
        {0, 3},
        {3, 2},
        {2, 1},
        {0, 1},
        {0, 4},
        {3, 4},
    };

    int l[7] = {4, 3, 2, 10, 100, 7, 9};

    int p[2] = {1, 3};

    cout << travel_plan(n, m, r, l, k, p) << endl;
}

#endif

Compilation message (stderr)

crocodile.cpp: In function 'long long int dijkstra()':
crocodile.cpp:25:22: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<std::map<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   25 |     for (ll i = 0; i < graph.size(); i++) {
      |                    ~~^~~~~~~~~~~~~~

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