제출 #1323320

#제출 시각아이디문제언어결과실행 시간메모리
1323320orkagCommuter Pass (JOI18_commuter_pass)C++20
100 / 100
236 ms23904 KiB
#include <bits/stdc++.h>
#include <queue>
#include <vector>
using namespace std;

#define ll long long
#define pb push_back
#define F first
#define S second
#define pii pair<int,int>
#define vi vector<int>
#define vpii vector<pii>

#define loop(i,n) sloop(0,i,n)
#define sloop(s, i, n) for(int i=(s);i<(n);i++)
#define rloop(i,n) rsloop(0,i,n)
#define rsloop(s,i,n) for(int i=(n);i-->(s);)

#define all(v) (v).begin(),(v).end()

#define nie {cout<<"No\n";return;}
#define tak {cout<<"Yes\n";return;}

#ifdef DEBUG
#define DBG cout << __LINE__ << endl;
#else 
#define DBG
#endif 

//int xses[8] = {-1,1,0,0,-1,1,1,-1};
//int yses[8] = {0,0,-1,1,-1,1,-1,1};

#define int ll

vector<vpii>g;

void dij(vi&odl,int start){
	priority_queue<pii,vpii,greater<pii>>pq;
	pq.push({0,start});

	while(pq.size()){
		auto [w,cur] = pq.top();
		pq.pop();

		if(odl[cur]!=INT_MAX)continue;
		odl[cur]=w;

		for(pii i:g[cur]){
			if(odl[i.F]==INT_MAX)
				pq.push({i.S+w,i.F});
		}
	}
}

void solve()
{
	int n,m;
	cin>>n>>m;
	g.assign(n,vpii());
	int s,t,u,v;
	cin>>s>>t>>u>>v;
	--s;--t;--u;--v;

	loop(i,m){
		int a,b,c;
		cin>>a>>b>>c;
		--a;--b;
		g[a].pb({b,c});
		g[b].pb({a,c});
	}

	vector<vi> odl(4,vi(n,INT_MAX)); //s, t, u, v 
	
	dij(odl[0],s);
	dij(odl[1],t);
	dij(odl[2],u);
	dij(odl[3],v);

	// 1. robie daga
	// 2. dp na dagu dp[i] ile odległości potrzebuje żeby dotrzeć z i do v
	// 3. odpowiedź to min z odl(u,i) dp[i]

	vector<vi> dag(n);
	loop(i,n){
		for(pii j:g[i]){
			if(odl[0][i]+odl[1][j.F]+j.S==odl[0][t]){
				dag[i].pb(j.F);
			}
		}
	}

	vi dp1(n,INT_MAX);
	vi dp2(n,INT_MAX);

	auto liczDP1 = [&](auto &Sf,int node) -> void{
		if(dp1[node]!=INT_MAX)return;
		dp1[node] = odl[3][node];
		for(int i:dag[node]){
			if(dp1[i]==INT_MAX)Sf(Sf,i);
			dp1[node]=min(dp1[node],dp1[i]);
		}
	};

	auto liczDP2 = [&](auto &Sf,int node) -> void{
		if(dp2[node]!=INT_MAX)return;
		dp2[node] = odl[2][node];
		for(int i:dag[node]){
			if(dp2[i]==INT_MAX)Sf(Sf,i);
			dp2[node]=min(dp2[node],dp2[i]);
		}
	};
	loop(i,n)liczDP1(liczDP1,i);
	loop(i,n)liczDP2(liczDP2,i);

	int res=odl[2][v];

	loop(i,n){
		res=min(res,odl[2][i]+dp1[i]);
		res=min(res,odl[3][i]+dp2[i]);
	}

	/*
	loop(i,n){
		cout<<i<<": ";
		for(int j:dag[i]){
			cout<<j<<' ';
		}
		cout<<'\n';
	}
	*/

	/*
	loop(i,n)cout<<dp[i]<<' ';
	cout<<'\n';
	*/


	cout<<res<<'\n';
}

signed main()
{
	cin.tie(0);
	ios_base::sync_with_stdio(0);

	int t=1;


	//cin>>t;
	loop(i,t)
	{
	#ifdef DEBUG

		if(t!=1)
		{
			cout<<"Test no. "<<i+1<<endl;
		}
	#endif
	
		solve();
	}

	#ifdef DEBUG
	cout << '\n';
	#endif
	return 0;
}
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