Submission #1129870

#	Time	Username	Problem	Language	Result	Execution time	Memory
1129870		julia_08	Commuter Pass (JOI18_commuter_pass)	C++20	31 / 100	669 ms	48140 KiB

commuter_pass

#include <bits/stdc++.h>
#define int long long

using namespace std;

const int MAXN = 2e5 + 10;
const int INF = 1e18;

vector<pair<int, int>> adj[MAXN];

map<pair<int, int>, int> marc_edge;

int marc[MAXN][3], dist[MAXN][3];

int n, m;

void dijkstra(int v, int x){

  for(int i=1; i<=n; i++){
    dist[i][x] = INF;
  }

  priority_queue<pair<int, int>> q;

  dist[v][x] = 0; q.push({0, v});

  while(!q.empty()){

    auto [d, v] = q.top(); q.pop();

    if(marc[v][x]) continue;

    marc[v][x] = 1;

    for(auto [u, w] : adj[v]){

      if(marc_edge[{v, u}]) w = 0;

      if(dist[v][x] + w < dist[u][x]){
        dist[u][x] = dist[v][x] + w;
        q.push({-dist[u][x], u});
      }
    }

  }

}

int32_t main(){
  cin.tie(0)->sync_with_stdio(0);

  cin >> n >> m;

  int s, t; cin >> s >> t;

  int u, v; cin >> u >> v;

  for(int i=1; i<=m; i++){
    int a, b, c; cin >> a >> b >> c;

    adj[a].push_back({b, c});
    adj[b].push_back({a, c});
  }

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

  int min_dist = dist[t][0];

  for(int i=1; i<=n; i++){

    for(auto [j, w] : adj[i]){
      if(dist[i][0] + dist[j][1] + w == min_dist){
        marc_edge[{i, j}] = marc_edge[{j, i}] = 1;
      }
    }

  }

  dijkstra(u, 2);

  cout << dist[v][2] << "\n";

  return 0;
}

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