Submission #1113413

#	Time	Username	Problem	Language	Result	Execution time	Memory
1113413		Dan4Life	Commuter Pass (JOI18_commuter_pass)	C++17	16 / 100	305 ms	43484 KiB

commuter_pass

#include <bits/stdc++.h>
using namespace std;
 
#define pb push_back
#define sz(a) (int)a.size()
#define all(a) begin(a),end(a)
 
using vi = vector<int>;
using ll = long long;
using ar2 = array<ll,2>;
 
const int N = (int)2e5+10;
const int INF = (int)1e9;
const ll LINF = (ll)2e18;
 
vi ts, adj2[N], radj[N];
int n, m, S, T, U, V;
ll dis[4][N], ans, D[N], D2[N], vis[N];
vector<ar2> adj[N];
vector<array<ll,3>> edges;
 
void dijkstra(int s, int t){
	priority_queue<ar2,vector<ar2>,greater<ar2>> pq;
	while(sz(pq)) pq.pop();
	for(int i = 1; i <= n; i++) dis[t][i]=LINF;
	dis[t][s] = 0; pq.push({0,s});
	while(sz(pq)){
		auto [D,a] = pq.top(); pq.pop();
		if(D!=dis[t][a]) continue;
		for(auto [b,w] : adj[a]){
			if(dis[t][a]+w<dis[t][b]){
				dis[t][b] = dis[t][a]+w;
				pq.push({dis[t][b],b});
			}
		}
	}
}
 
void dfs(int s,vector<int> adj[]){
	vis[s]=1;
	for(auto u : adj[s]) 
		if(!vis[u]) dfs(u,adj);
	ts.pb(s);
}
 
int main(){
	ios_base::sync_with_stdio(false); cin.tie(0);
	cin >> n >> m >> S >> T >> U >> V;
	for(int i = 0; i < m; i++){
		int a, b, c; cin >> a >> b >> c;
		adj[a].pb({b,c}), adj[b].pb({a,c});
		edges.pb({a,b,c});
	}
	dijkstra(S,0); dijkstra(T,1); dijkstra(U,2); dijkstra(V,3);
	for(int i = 1; i <= n; i++) adj[i].clear();
	ans = dis[2][V];
	for(auto [a,b,c] : edges){
		if(dis[0][a]+c+dis[1][b]==dis[0][T]) 
			adj2[a].pb(b), radj[b].pb(a);
		swap(a,b);
		if(dis[0][a]+c+dis[1][b]==dis[0][T]) 
			adj2[a].pb(b), radj[b].pb(a);
	}
	for(int i = 1; i <= n; i++) D[i]=dis[2][i], D2[i]=dis[3][i];
	dfs(S,adj2); reverse(all(ts));
	for(auto u : ts){
		D[u] = dis[2][u];
		for(auto v : radj[u])
			D[u] = min(D[u],D[v]);
	}
	ts.clear();
	dfs(T,radj); reverse(all(ts));
	for(auto u : ts){
		for(auto v : adj2[u])
			D2[u] = min(D2[u],D2[v]);
	}
	for(int i = 1; i <= n; i++) 
		ans = min(ans, D[i]+D2[i]);
	cout << ans << "\n";
}

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