Submission #784137

#	Time	Username	Problem	Language	Result	Execution time	Memory
784137		mars4	Valley (BOI19_valley)	C++17	100 / 100	232 ms	58216 KiB

valley

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp> 

using namespace std;
using namespace __gnu_pbds; 

#define ff              first
#define ss              second
#define ll              int64_t
#define ld              long double
#define nl              cout<<"\n"
#define i128            __int128_t
#define all(v)          v.begin(),v.end()
#define mset(a,v)       memset((a),(v),sizeof(a))
#define forn(i,a,b)     for(int64_t i=int64_t(a);i<int64_t(b);++i)
#define forb(i,a,b)     for(int64_t i=int64_t(a);i>=int64_t(b);--i)
#define fastio()        ios::sync_with_stdio(false); cin.tie(0); cout.tie(0);

#define mod         1'000'000'007
#define mod2        998'244'353 
#define inf         1'000'000'000'000'007
#define pi          3.14159265358979323846

template<class key,class cmp=std::less<key>>
using ordered_set=tree<key,null_type,cmp,rb_tree_tag,tree_order_statistics_node_update>;

template<class L,class R> ostream& operator<<(ostream& out,pair<L,R> &p)        {return out<<"("<<p.ff<<", "<<p.ss<<")";}
template<class T> ostream& operator<<(ostream& out,vector<T> &v)                {out<<"[";for(auto it=v.begin();it!=v.end();++it){if(it!=v.begin())out<<", ";out<<*it;}return out<<"]";}
template<class T> ostream& operator<<(ostream& out,deque<T> &v)                 {out<<"[";for(auto it=v.begin();it!=v.end();++it){if(it!=v.begin())out<<", ";out<<*it;}return out<<"]";}
template<class T> ostream& operator<<(ostream& out,set<T> &s)                   {out<<"{";for(auto it=s.begin();it!=s.end();++it){if(it!=s.begin())out<<", ";out<<*it;}return out<<"}";}
template<class T> ostream& operator<<(ostream& out,ordered_set<T> &s)           {out<<"{";for(auto it=s.begin();it!=s.end();++it){if(it!=s.begin())out<<", ";out<<*it;}return out<<"}";}
template<class L,class R> ostream& operator<<(ostream& out,map<L,R> &m)         {out<<"{";for(auto it=m.begin();it!=m.end();++it){if(it!=m.begin())out<<", ";out<<*it;}return out<<"}";}

void dbg_out() {cerr<<"]\n";}
template<typename Head,typename... Tail> 
void dbg_out(Head H,Tail... T) {cerr<<H;if(sizeof...(Tail))cerr<<", ";dbg_out(T...);}
#ifdef LOCAL
#define dbg(...) cerr<<"["<<#__VA_ARGS__<<"] = [",dbg_out(__VA_ARGS__)
#else
#define dbg(...)
#endif

//---------------------------------mars4---------------------------------

const ll logN=20;
vector<vector<pair<ll,ll>>> v;
vector<bool> mark;
vector<vector<ll>> jmp;
vector<vector<ll>> val;
vector<ll> st;
vector<ll> ed;
vector<ll> depth;
vector<ll> dist;
vector<ll> min_subtree_dist;
ll timer=-1;

void dfs(ll cur,ll prev)
{
	timer++;
	st[cur]=timer;
	jmp[cur][0]=prev;
	if(mark[cur])
	{
		min_subtree_dist[cur]=0;
	}
	for(auto [nxt,w]:v[cur])
	{
		if(nxt!=prev)
		{
			depth[nxt]=depth[cur]+1;
			dist[nxt]=dist[cur]+w;
			dfs(nxt,cur);
			min_subtree_dist[cur]=min(min_subtree_dist[cur],min_subtree_dist[nxt]+w);
		}
	}
	val[cur][0]=min_subtree_dist[cur]-dist[cur];
	ed[cur]=timer;
}

int main()
{
	fastio();
	ll z,n,m,t,k,i,j,l,d,h,r;
	ll q,root;
	cin>>n>>m>>q>>root;
	root--;
	v=vector<vector<pair<ll,ll>>>(n);
	jmp=vector<vector<ll>>(n,vector<ll>(logN));
	val=vector<vector<ll>>(n,vector<ll>(logN));
	st=vector<ll>(n);
	ed=vector<ll>(n);
	depth=vector<ll>(n);
	dist=vector<ll>(n);
	min_subtree_dist=vector<ll>(n,inf);
	mark=vector<bool>(n);
	vector<pair<ll,ll>> edges(n-1);
	forn(i,0,n-1)
	{
		cin>>l>>r>>d;
		l--,r--;
		v[l].push_back({r,d});
		v[r].push_back({l,d});
		edges[i]={l,r};
	}
	forn(i,0,m)
	{
		cin>>d;
		mark[d-1]=true;
	}
	dfs(root,root);
	forn(j,1,logN)
	{
		forn(i,0,n)
		{
			jmp[i][j]=jmp[jmp[i][j-1]][j-1];
			val[i][j]=min(val[i][j-1],val[jmp[i][j-1]][j-1]);
		}
	}
	auto calc=[&](ll cur,ll jumps)
	{
		ll res=inf;
		ll cdist=dist[cur];
		forb(i,logN-1,0)
		{
			if(jumps&(1ll<<i))
			{
				res=min(res,val[cur][i]);
				cur=jmp[cur][i];
			}
		}
		return res+cdist;
	};
	forn(i,0,q)
	{
		cin>>k>>d;
		k--,d--;
		auto [l,r]=edges[k];
		if(depth[l]<depth[r])
		{
			swap(l,r);
		}
		if(st[l]<=st[d] and ed[l]>=st[d])
		{
			ll jumps=depth[d]-depth[l]+1; // add 1 since we are not counting from parent
			ll res=calc(d,jumps);
			if(res>=inf)
			{
				cout<<"oo\n";
			}
			else
			{
				cout<<res<<"\n";
			}
		}
		else
		{
			cout<<"escaped\n";
		}
	}
	cerr<<"\nTime elapsed: "<<1000*clock()/CLOCKS_PER_SEC<<"ms\n";
	return 0;
}

Compilation message (stderr)

valley.cpp: In function 'int main()':
valley.cpp:84:5: warning: unused variable 'z' [-Wunused-variable]
   84 |  ll z,n,m,t,k,i,j,l,d,h,r;
      |     ^
valley.cpp:84:11: warning: unused variable 't' [-Wunused-variable]
   84 |  ll z,n,m,t,k,i,j,l,d,h,r;
      |           ^
valley.cpp:84:15: warning: unused variable 'i' [-Wunused-variable]
   84 |  ll z,n,m,t,k,i,j,l,d,h,r;
      |               ^
valley.cpp:84:17: warning: unused variable 'j' [-Wunused-variable]
   84 |  ll z,n,m,t,k,i,j,l,d,h,r;
      |                 ^
valley.cpp:84:23: warning: unused variable 'h' [-Wunused-variable]
   84 |  ll z,n,m,t,k,i,j,l,d,h,r;
      |                       ^

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