Submission #548387

#	Time	Username	Problem	Language	Result	Execution time	Memory
548387		FEDIKUS	Commuter Pass (JOI18_commuter_pass)	C++17	100 / 100	387 ms	33092 KiB

commuter_pass

#include <bits/stdc++.h>
#define mp make_pair
#define pb push_back
#define pf push_front
#define popb pop_back
#define popf pop_front
#define xx first
#define yy second
#define srt(a) sort(a.begin(),a.end());
#define srtg(a,ll) sort(a.begin(),a.end(),greater<ll>())
#define lb(a,x) lower_bound(a.begin(),a.end(),x)
#define up(a,x) upper_bound(a.begin(),a.end(),x)
#define fnd(a,x) find(a.begin(),a.end(),x)
#define vstart auto startt=chrono::system_clock::now()
#define vend auto endd=chrono::system_clock::now()
#define vvreme chrono::duration<double> vremee=endd-startt
#define ios ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0)

using namespace std;

typedef long long ll;
typedef pair<ll,ll> pii;
typedef pair<ll,ll> pll;
typedef string str;

const ll maxn=1e5+10;

vector<pair<ll,ll> > g[maxn];
vector<ll> ng[maxn];
ll dists[maxn],distu[maxn],distv[maxn];
ll n,m,s,t,u,v;
ll res=LLONG_MAX;
bool bio[maxn];
pii naj[maxn];

void dijkstra(ll poc,ll* dist){
	priority_queue<pii,vector<pii>,greater<pii> > pq;
	for(ll i=1;i<=n;i++) dist[i]=LLONG_MAX;
	dist[poc]=0;
	pq.push(mp(0,poc));
	while(!pq.empty()){
		auto tren=pq.top();
		pq.pop();
		if(dist[tren.yy]<tren.xx) continue;
		for(pii i:g[tren.yy]){
			if(dist[i.xx]>dist[tren.yy]+i.yy){
				dist[i.xx]=dist[tren.yy]+i.yy;
				pq.push(mp(dist[i.xx],i.xx));
			}
		}
	}
}

void dfs(ll cvor){
	if(bio[cvor]) return;
	bio[cvor]=true;
	naj[cvor]={LLONG_MAX,LLONG_MAX};
	if(cvor==t) naj[cvor]={distu[cvor],distv[cvor]};
	for(ll i:ng[cvor]){
		dfs(i);
		naj[cvor].xx=min(naj[cvor].xx,naj[i].xx);
		naj[cvor].yy=min(naj[cvor].yy,naj[i].yy);
	}
	if(naj[cvor].xx!=LLONG_MAX){
		naj[cvor].xx=min(naj[cvor].xx,distu[cvor]);
		naj[cvor].yy=min(naj[cvor].yy,distv[cvor]);
		res=min(res,min(distu[cvor]+naj[cvor].yy,distv[cvor]+naj[cvor].xx));
	}
}

void solve(){
	cin>>n>>m;
	cin>>s>>t;
	cin>>u>>v;
	for(ll i=0;i<m;i++){
		ll a,b,c;
		cin>>a>>b>>c;
		g[a].pb(mp(b,c));
		g[b].pb(mp(a,c));
	}
	dijkstra(s,dists);
	dijkstra(u,distu);
	dijkstra(v,distv);
	for(ll i=1;i<=n;i++){
		for(pii j:g[i]){
			if(dists[i]+j.yy==dists[j.xx]){
				ng[i].pb(j.xx);
			}
		}
	}
	dfs(s);
	cout<<min(res,distu[v]);
}

int main(){
    //ios;
    ll t=1;
    //cin>>t;
    while(t--) solve();
    return 0;
}

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