Submission #701790

#	Time	Username	Problem	Language	Result	Execution time	Memory
701790		mychecksedad	Commuter Pass (JOI18_commuter_pass)	C++17	31 / 100	283 ms	43048 KiB

commuter_pass

/* Author : Mychecksdead */
#include<bits/stdc++.h>
using namespace std;
typedef long long int ll;
#define MOD (1000000000+7)
#define MOD1 (998244353)
#define PI 3.1415926535
#define pb push_back
#define all(x) x.begin(), x.end()
const int N = 1e6+100, M = 1e5+10, K = 20;
 
 
int n, m, s, t, x, y;
ll d[N];
vector<array<ll, 3>> g[N];
vector<bool> vis;
vector<array<int, 2>> good;
 
void solve(){
  cin >> n >> m >> s >> t >> x >> y;
  for(int i = 0; i < m; ++i){
    int u, v, w; cin >> u >> v >> w;
    g[u].pb({v, w, i});
    g[v].pb({u, w, i});
  }
  vis.resize(n + 1);
  good.resize(m);
  priority_queue<pair<ll, int>> q;
  q.push({0, s});
  for(int i = 1; i <= n; ++i) d[i] = i == s ? 0 : LONG_LONG_MAX;
  while(!q.empty()){
    int v = q.top().second; q.pop();
    if(vis[v]) continue;
    vis[v] = 1;
    for(auto U: g[v]){
      ll u = U[0], w = U[1];
      if(!vis[u] && d[u] > d[v] + w){
        d[u] = d[v] + w;
        q.push({-d[u], u});
      }
    }
  }
  queue<int> Q;
  Q.push(t);
  fill(all(vis), 0);
  vis[t] = 1;
  while(!Q.empty()){
    int v = Q.front(); Q.pop();
    for(auto U: g[v]){
      ll u = U[0], w = U[1];
      if(d[u] == d[v] - w){
        good[U[2]] = {v, u};
        if(!vis[u]){
          vis[u] = 1;
          Q.push(u);
        }
      }
    }
  }
  ll ans = LONG_LONG_MAX;
  for(int rep = 0; rep < 2; ++rep){
    for(int i = 1; i <= n; ++i) d[i] = LONG_LONG_MAX;
    d[x] = 0;
    q.push({0, x});
    fill(all(vis), 0);
    while(!q.empty()){
      int v = q.top().second; q.pop();
      if(vis[v]) continue;
      vis[v] = 1;
      for(auto U: g[v]){
        ll u = U[0], w = U[1];
        if(good[U[2]][rep] == v && good[U[2]][rep^1] == u) w = 0;
        if(!vis[u] && d[u] > d[v] + w){
          d[u] = d[v] + w;
          q.push({-d[u], u});
        }
      }
    }
    ans = min(ans, d[y]);
  }
  cout << ans;
}
 
 
int main(){
  cin.tie(0); ios::sync_with_stdio(0);
  int T = 1, aa;
  // cin >> T;aa=T;
  while(T--){
    // cout << "Case #" << aa-T << ": ";
    solve();
    cout << '\n';
  }
  return 0;
 
}

Compilation message (stderr)

commuter_pass.cpp: In function 'void solve()':
commuter_pass.cpp:52:26: warning: narrowing conversion of 'u' from 'll' {aka 'long long int'} to 'int' [-Wnarrowing]
   52 |         good[U[2]] = {v, u};
      |                          ^
commuter_pass.cpp: In function 'int main()':
commuter_pass.cpp:87:14: warning: unused variable 'aa' [-Wunused-variable]
   87 |   int T = 1, aa;
      |              ^~

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