Submission #293396

#	Time	Username	Problem	Language	Result	Execution time	Memory
293396		rama_pang	Commuter Pass (JOI18_commuter_pass)	C++14	31 / 100	663 ms	48500 KiB

commuter_pass

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

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

  int N, M, S, T, U, V;
  cin >> N >> M >> S >> T >> U >> V;
  S--, T--, U--, V--;

  vector<array<int, 3>> edges;
  vector<vector<pair<int, int>>> adj(N);
  for (int i = 0; i < M; i++) {
    int u, v, w;
    cin >> u >> v >> w;
    u--, v--;
    adj[u].emplace_back(v, w);
    adj[v].emplace_back(u, w);
    edges.push_back({u, v, w});
    edges.push_back({v, u, w});
  }

  auto Dijkstra = [&](int s, int t, vector<vector<pair<int, int>>> nadj = vector<vector<pair<int, int>>>()) {
    vector<lint> dist(N, -1);
    priority_queue<pair<lint, int>, vector<pair<lint, int>>, greater<pair<lint, int>>> pq;
    pq.emplace(0, s);
    dist[s] = 0;
    while (!pq.empty()) {
      int u = pq.top().second;
      lint d = pq.top().first;
      pq.pop();
      if (dist[u] != d) {
        continue;
      }
      for (auto v : adj[u]) {
        if (dist[v.first] == -1 || dist[v.first] > dist[u] + v.second) {
          dist[v.first] = dist[u] + v.second;
          pq.emplace(dist[v.first], v.first);
        }
      }
      if (!nadj.empty()) {
        for (auto v : nadj[u]) {
          if (dist[v.first] == -1 || dist[v.first] > dist[u] + v.second) {
            dist[v.first] = dist[u] + v.second;
            pq.emplace(dist[v.first], v.first);
          }
        } 
      }
    }
    return make_pair(dist, dist[t]);
  };

  vector<lint> dS = Dijkstra(S, T).first;
  vector<lint> dT = Dijkstra(T, S).first;
  vector<vector<pair<int, int>>> nadj1(N), nadj2(N);
  for (int i = 0; i < 2 * M; i++) {
    int u = edges[i][0], v = edges[i][1], w = edges[i][2];
    if( dS[u] + dT[v] + w == dS[T]) {
      nadj1[u].emplace_back(v, 0);
      nadj2[v].emplace_back(u, 0);
    }
  }

  cout << min({Dijkstra(U, V, nadj1).second, Dijkstra(U, V, nadj2).second, 
               Dijkstra(V, U, nadj1).second, Dijkstra(V, U, nadj2).second}) << "\n";
  return 0;
}

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