Submission #923816

#	Time	Username	Problem	Language	Result	Execution time	Memory
923816		VMaksimoski008	Commuter Pass (JOI18_commuter_pass)	C++14	31 / 100	316 ms	22524 KiB

commuter_pass

#include <bits/stdc++.h>

#define sz(x) (int)x.size()
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define int long long

using namespace std;

using ll = long long;
using ull = unsigned long long;
using ld = long double;
using pii = pair<int, int>;
using pll = pair<ll, ll>;

const int mod = 1e9 + 7;
const int LOG = 20;
const int maxn = 1e5 + 5;
const double eps = 1e-9;

int32_t main() {
    int n, m, s, t, U, V;
    cin >> n >> m >> s >> t >> U >> V;

    vector<vector<pii> > graph(n+1);

    for(int i=0; i<m; i++) {
        int a, b, w;
        cin >> a >> b >> w;
        graph[a].push_back({ b, w });
        graph[b].push_back({ a, w });
    }

    vector<vector<ll> > dist(3, vector<ll>(n+1, 1e18));

    auto dijkstra = [&](int start, int id) {
        vector<bool> vis(n+1);
        priority_queue<pll, vector<pll>, greater<pll> > pq;

        dist[id][start] = 0;
        pq.push({ 0, start });

        while(!pq.empty()) {
            int u = pq.top().second;
            pq.pop();

            if(vis[u]) continue;
            vis[u] = 1;

            for(auto &[v, w] : graph[u]) {
                if(dist[id][v] > dist[id][u] + w) {
                    dist[id][v] = dist[id][u] + w;
                    pq.push({ dist[id][v], v });
                }
            }
        }
    };

    dijkstra(s, 0); dijkstra(t, 1);

    ll SP = dist[0][t];

    auto lies_on_sp = [&](int u, int v, int w) {
        ll cost1 = dist[0][u] + dist[1][v] + w;
        ll cost2 = dist[1][u] + dist[0][v] + w;
        return min(cost1, cost2) == SP;
    };

    vector<bool> vis(n+1);
    priority_queue<pll, vector<pll>, greater<pll> > pq;

    pq.push({ 0, U });
    dist[2][U] = 0;

    while(!pq.empty()) {
        int u = pq.top().second;
        pq.pop();

        if(vis[u]) continue;
        vis[u] = 1;

        for(auto &[v, w] : graph[u]) {
            ll cost = (lies_on_sp(u, v, w) ? 0 : w);
            if(dist[2][v] > dist[2][u] + cost) {
                dist[2][v] = dist[2][u] + cost;
                pq.push({ dist[2][v], v });
            }
        }
    }

    cout << dist[2][V] << '\n';
    return 0;
}

Compilation message (stderr)

commuter_pass.cpp: In lambda function:
commuter_pass.cpp:50:23: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   50 |             for(auto &[v, w] : graph[u]) {
      |                       ^
commuter_pass.cpp: In function 'int32_t main()':
commuter_pass.cpp:82:19: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   82 |         for(auto &[v, w] : graph[u]) {
      |                   ^

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