Submission #1140878

#	Time	Username	Problem	Language	Result	Execution time	Memory
1140878		buzdi	Commuter Pass (JOI18_commuter_pass)	C++17	31 / 100	257 ms	26516 KiB

commuter_pass

#include <bits/stdc++.h>

#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
 
#define ll long long
#define ld long double

using namespace std;
using namespace __gnu_pbds;

typedef tree<int, null_type, less<int>, rb_tree_tag, tree_order_statistics_node_update> ordered_set;

const int NMAX = 1e5;
const ll INF = 1e18;

struct PQElement {
    int node;
    ll d;
    bool operator < (const PQElement &other) const {
        return other.d < d;
    }
};

int n, m, s, t, x, y;
vector<pair<int, int>> g[2][NMAX + 1];
ll d[2][NMAX + 1];

void Dijkstra(int start, int which_start, int which_graph) {
    for(int i = 1; i <= n; i++) {
        d[which_start][i] = INF;
    }
    
    priority_queue<PQElement> pq;
    pq.push({start, 0});
    while(!pq.empty()) {
        auto [node, curent_d] = pq.top();
        pq.pop();

        if(d[which_start][node] == INF) {
            d[which_start][node] = curent_d;
            for(auto [next_node, edge_d] : g[which_graph][node]) {
                pq.push({next_node, curent_d + edge_d});
            }
        } 
    }
}

void CreateNewGraph() {
    for(int i = 1; i <= n; i++) {
        for(auto [j, edge_d] : g[0][i]) {
            if(d[0][i] + edge_d + d[1][j] == d[0][t]) {
                g[1][i].emplace_back(j, 0);
                g[1][j].emplace_back(i, 0);
            }
            else {
                g[1][i].emplace_back(j, edge_d);
            }
        }
    }
}

int main() {
    ios::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);

    cin >> n >> m >> s >> t >> x >> y;
    for(int i = 1; i <= m; i++) {
        int a, b, c;
        cin >> a >> b >> c;
        g[0][a].emplace_back(b, c);
        g[0][b].emplace_back(a, c);
    }

    Dijkstra(s, 0, 0);
    Dijkstra(t, 1, 0);
    CreateNewGraph();

    // cout << '\n';
    // for(int i = 1; i <= n; i++) {
    //     for(auto [j, edge_d] : g[1][i]) {
    //         cout << i << ' ' << j << ' ' << edge_d << '\n';
    //     }
    // }

    Dijkstra(x, 0, 1);
    cout << d[0][y] << '\n';

    return 0;
}

• Subtask 1: 16 / 16
• Subtask 2: 15 / 15
• Subtask 3: 0 / 24
• Subtask 4: 0 / 45