Submission #293400

#	Time	Username	Problem	Language	Result	Execution time	Memory
293400		rama_pang	Commuter Pass (JOI18_commuter_pass)	C++14	100 / 100	451 ms	20724 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<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);
  }

  auto Dijkstra = [&](int s) {
    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);
        }
      }
    }
    return dist;
  };

  vector<lint> dS = Dijkstra(S);
  vector<lint> dT = Dijkstra(T);
  vector<lint> dU = Dijkstra(U);
  vector<lint> dV = Dijkstra(V);

  vector<int> order(N);
  iota(begin(order), end(order), 0);
  sort(begin(order), end(order), [&](int i, int j) {
    return dS[i] < dS[j];
  });

  auto Calc = [&](int A, int B, vector<lint> dA, vector<lint> dB) {
    vector<lint> dp(N);
    lint ans = 1e18;
    for (auto u : order) {
      if (dS[u] + dT[u] == dS[T]) {
        dp[u] = dA[u];
        for (auto v : adj[u]) if (dS[v.first] + dT[v.first] == dS[T] && dS[v.first] < dS[u]) {
          dp[u] = min(dp[u], dp[v.first]);
        }
        ans = min(ans, dp[u] + dB[u]);
      } else {
        ans = min(ans, dA[u] + dB[u]);
      }
    }
    return ans;
  };

  cout << min(Calc(U, V, dU, dV), Calc(V, U, dV, dU)) << "\n";
  return 0;
}

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