Submission #43803

#	Time	Username	Problem	Language	Result	Execution time	Memory
43803		wzy	Commuter Pass (JOI18_commuter_pass)	C++11	100 / 100	599 ms	146920 KiB

commuter_pass

#include <bits/stdc++.h>
using namespace std;
#define pii pair<long long,long long>
#define pb push_back
#define ppi pair<pii , pii>
#define piii pair<long long,ppi >
#define F first
#define S second 
long long f1[100005] , f2[100005]  , f3[100005] ;
int n , m ;
vector<pii> adj[100005];
int s, t , u , v;


int main(){
	cin>>n>>m;
	cin>>s>>t>>u>>v;
	for(int i = 0 ; i < m ; i ++){
		int x , y , z;
		cin>>x>>y>>z;
		adj[x].pb(pii(z,y));
		adj[y].pb(pii(z,x));
	}
	for(int i = 1 ; i <= n; i++){
		f1[i] = (long long) 1e18 , f2[i] = (long long) 1e18 , f3[i] = (long long) 1e18;
	}
	priority_queue<pii , vector<pii> , greater<pii> > pq;
	pq.push(pii(0 , u));
	while(!pq.empty()){
		pii u = pq.top();
		pq.pop();
		if(u.F >= f1[u.S]) continue;
		f1[u.S] = u.F;
		for(auto p : adj[u.S]){
			if(f1[p.S] > p.F + u.F){
				pq.push(pii(p.F + u.F , p.S));
			}
		}
	}
	pq.push(pii(0 , v));
	while(!pq.empty()){
		pii u = pq.top();
		pq.pop();
		if(u.F >= f2[u.S]) continue;
		f2[u.S] = u.F;
		for(auto p : adj[u.S]){
			if(f2[p.S] > p.F + u.F){
				pq.push(pii(p.F + u.F , p.S));
			}
		}
	}
	long long ans = f2[u];
	priority_queue< piii , vector<piii> , greater<piii> > pqq;
	pqq.push(piii(0 , ppi(pii(f1[s] + f2[s] , s) , pii(f1[s]  , f2[s]))));
	while(!pqq.empty()){
		piii u = pqq.top();
		pqq.pop();
		if(f3[u.S.F.S] <= u.F) continue;
		if(u.S.F.S == t){
			ans = min(ans , u.S.F.F);
			break;
		}
		f3[u.S.F.S] = u.F;
		for(auto p : adj[u.S.F.S]){
			if(f3[p.S] > u.F + p.F){
				pii w = u.S.S;
				w.F = min(w.F , f1[p.S]) , w.S = min(w.S , f2[p.S]);
				pqq.push(piii(u.F + p.F , ppi(pii(w.F + w.S, p.S) , w )));
			}
		}
	}
	cout<<ans<<endl;

}

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