Submission #147713

#	Time	Username	Problem	Language	Result	Execution time	Memory
147713		MvC	Valley (BOI19_valley)	C++11	100 / 100	411 ms	77304 KiB

valley

#pragma GCC target("avx2")
#pragma GCC optimization("O3")
#pragma GCC optimization("unroll-loops")
#include<bits/stdc++.h>
//#include "boxes.h"
#define rc(x) return cout<<x<<endl,0
#define pb push_back
#define mkp make_pair
#define in insert
#define er erase
#define fd find
#define fr first
#define sc second
typedef long long ll;
typedef long double ld;
const ll INF=0x3f3f3f3f3f3f3f3f;
const ll llinf=(1LL<<61);
const int inf=(1<<30);
const int nmax=1e5+50;
const int mod=1e9+7;
using namespace std;
int n,s,q,e,x,y,ex[nmax],ey[nmax],par[nmax][20],fin[nmax],fout[nmax],b[nmax],i,tin,v,l;
ll w,ew[nmax],h[nmax],w1,w2,up[nmax],dw[nmax],u[nmax][20],d[nmax][20],w3,vl[nmax],vd[nmax],vu[nmax];
vector<pair<int,ll> >a[nmax];
vector<pair<ll,int> >vc[nmax],vec[nmax];
void dfsdw(int x,int p)
{
	if(b[x])vc[x].pb(mkp(0,x));
	for(int i=0;i<a[x].size();i++)
	{
		int y=a[x][i].fr;
		if(y==p)continue;
		dfsdw(y,x);
		if(vc[y].empty())continue;
		vc[x].pb(mkp(vc[y][0].fr+a[x][i].sc,y));
		sort(vc[x].begin(),vc[x].end());
		if(vc[x].size()==3)vc[x].pop_back();
	}
	vec[x]=vc[x];
}
void dfsup(int x,int p,ll z)
{
	up[x]=dw[x]=llinf;
	if(!vc[x].empty())dw[x]=vc[x][0].fr;
	if(b[x])up[x]=0;
	if(x!=p && up[x])
	{
		for(int i=0;i<vc[p].size();i++)
		{
			int y=vc[p][i].sc;
			if(y!=x)
			{
				up[x]=vc[p][i].fr+z;
				vc[x].pb(mkp(up[x],p));
				sort(vc[x].begin(),vc[x].end());
				if(vc[x].size()==3)vc[x].pop_back();
				break;
			}
		}
	}
	for(int i=0;i<a[x].size();i++)
	{
		int y=a[x][i].fr;
		if(y==p)continue;
		dfsup(y,x,a[x][i].sc);
	}
}
void build(int x,int p,ll z)
{
	vl[x]=z;
	par[x][0]=p;
	h[x]=h[p]+z;
	d[x][0]=u[x][0]=vd[x]=vu[x]=llinf;
	if(dw[x]!=llinf)vd[x]=dw[x]-h[x];
	if(dw[p]!=llinf)d[x][0]=dw[p]-h[p];
	if(up[x]!=llinf)
	{
		if(up[x])vu[x]=up[x]-vl[x]+h[x];
		else vu[x]=up[x]+h[x];
	}
	if(up[p]!=llinf)
	{
		if(up[p])u[x][0]=up[p]-vl[p]+h[p];
		else u[x][0]=up[p]+h[p];
	}
	fin[x]=++tin;
	for(int i=1;i<18;i++)
	{
		par[x][i]=par[par[x][i-1]][i-1];
		d[x][i]=u[x][i]=llinf;
		d[x][i]=min(d[x][i-1],d[par[x][i-1]][i-1]);
		u[x][i]=min(u[x][i-1],u[par[x][i-1]][i-1]);
	}
	for(int i=0;i<a[x].size();i++)
	{
		int y=a[x][i].fr;
		if(y==p)continue;
		build(y,x,a[x][i].sc);
	}
	fout[x]=++tin;
}
int anc(int x,int y)
{
	return fin[x]<=fin[y] && fout[y]<=fout[x];
}
ll fnd(int x,int y,int bl)
{
	ll rs=llinf;
	rs=min(rs,vd[x]);
	for(int i=17;i>=0;i--)
	{
		if(!anc(par[x][i],y))
		{
			rs=min(rs,d[x][i]);
			x=par[x][i];
			rs=min(rs,vd[x]);
		}
	}
	if(bl && x!=y)
	{
		rs=min(rs,d[x][0]);
	}
	return rs;
}
ll fnu(int x,int y)
{
	ll rs=llinf;
	rs=min(rs,vu[x]);
	for(int i=17;i>=0;i--)
	{
		if(!anc(par[x][i],y))
		{
			rs=min(rs,u[x][i]);
			x=par[x][i];
			rs=min(rs,vu[x]);
		}
	}
	return rs;
}
int lca(int x,int y)
{
	if(anc(x,y))return x;
	if(anc(y,x))return y;
	for(int i=17;i>=0;i--)if(!anc(par[x][i],y))x=par[x][i];
	return par[x][0];
}
int main()
{
	//freopen("sol.in","r",stdin);
	//freopen("sol.out","w",stdout);
	//mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
	ios_base::sync_with_stdio(false);cin.tie(0);cerr.tie(0);cout.tie(0);
	cin>>n>>s>>q>>e;
	for(i=1;i<n;i++)
	{
		cin>>x>>y>>w;
		a[x].pb(mkp(y,w));
		a[y].pb(mkp(x,w));
		ex[i]=x,ey[i]=y,ew[i]=w;
	}
	for(i=1;i<=s;i++)
	{
		cin>>x;
		b[x]=1;
	}
	dfsdw(e,e);
	dfsup(e,e,0);
	build(e,e,0);
	while(q--)
	{
		cin>>x>>y;
		if(h[ex[x]]>h[ey[x]])swap(ex[x],ey[x]);
		v=ex[x];
		x=ey[x];
		if(!anc(x,y))cout<<"escaped\n";
		else
		{
			w=fnd(y,x,1);
			if(w!=llinf)w+=h[y];
			if(w==llinf)cout<<"oo\n";
			else cout<<w<<'\n';
		}
	}
	return 0;
}

Compilation message (stderr)

valley.cpp:2:0: warning: ignoring #pragma GCC optimization [-Wunknown-pragmas]
 #pragma GCC optimization("O3")
 
valley.cpp:3:0: warning: ignoring #pragma GCC optimization [-Wunknown-pragmas]
 #pragma GCC optimization("unroll-loops")
 
valley.cpp: In function 'void dfsdw(int, int)':
valley.cpp:29:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=0;i<a[x].size();i++)
              ~^~~~~~~~~~~~
valley.cpp: In function 'void dfsup(int, int, ll)':
valley.cpp:48:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(int i=0;i<vc[p].size();i++)
               ~^~~~~~~~~~~~~
valley.cpp:61:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=0;i<a[x].size();i++)
              ~^~~~~~~~~~~~
valley.cpp: In function 'void build(int, int, ll)':
valley.cpp:94:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=0;i<a[x].size();i++)
              ~^~~~~~~~~~~~

• Subtask 1: 9 / 9
• Subtask 2: 27 / 27
• Subtask 3: 23 / 23
• Subtask 4: 41 / 41