Submission #817856

#	Time	Username	Problem	Language	Result	Execution time	Memory
817856		MohamedAhmed04	Inside information (BOI21_servers)	C++14	65 / 100	3570 ms	49408 KiB

servers

#include <bits/stdc++.h>

using namespace std ;

const int MAX = 3e5 + 10 ;
const int B = 2004 ;

int n , q ;

vector< vector< pair<int , int> > >adj(MAX) ;
vector< vector<int> >adj2(MAX) ;

int val[MAX] , up_inc[MAX] , up_dec[MAX] ;
int dep[MAX] , P[MAX][18] ;

int in[MAX] , out[MAX] ;
int tim = 0 ;

void dfs(int node , int par)
{
	in[node] = ++tim ;
	P[node][0] = par ;
	for(int i = 1 ; i < 18 ; ++i)
		P[node][i] = P[P[node][i-1]][i-1] ;
	up_inc[node] = up_dec[node] = par ;
	if(val[node] < val[par])
		up_inc[node] = up_inc[par] ;
	else
		up_dec[node] = up_dec[par] ;
	for(auto &childd : adj[node])
	{
		int child = childd.first , y = childd.second ;
		if(child == par)
			continue ;
		dep[child] = dep[node] + 1 , val[child] = y ;
		dfs(child , node) ;
	}
	out[node] = tim ;
}

bool Ancestor(int x , int y)
{
	return (in[y] >= in[x] && in[y] <= out[x]) ;
}

bool check(int x , int y , int tim) // x has server y
{
	if(x == y)
		return true ;
	if((!Ancestor(up_inc[y] , x)))
		return false ;
	if((!Ancestor(up_dec[x] , y)))
		return false ;
	if(Ancestor(y , x))
		return (val[x] <= tim) ;
	if((!Ancestor(x , y)) && val[x] > tim)
		return false ;
	bool flag = false ;
	if(dep[x] < dep[y])
		swap(x , y) , flag = true ;
	for(int k = 17 ; k >= 0 ; --k)
	{
		if(dep[x] - (1 << k) > dep[y])
			x = P[x][k] ;
	}
	if(P[x][0] == y)
		return (val[x] <= tim) ;
	if(dep[x] != dep[y])
		x = P[x][0] ;
	if(flag)
		swap(x , y) ;
	for(int k = 17 ; k >= 0 ; --k)
	{
		if(P[x][k] != P[y][k])
			x = P[x][k] , y = P[y][k] ;
	}
	return (val[x] > val[y]) ;
}

int dp[MAX] , dpup[MAX] , dpdown[MAX] ;
int vis[MAX] ;

void dfs2(int node , int par)
{
	vis[node] = 1 ;
	dpdown[node] = dp[node] = 1 ;
	for(auto &child : adj2[node])
	{
		if(child == par)
			continue ;
		dfs2(child , node) ;
		if(val[child] > val[node])
			dpdown[node] += dpdown[child] ;
		dp[node] += dpdown[child] ;
	}
}

void dfs3(int node , int par , int sum)
{
	dpup[node] = sum + (par != node) ;
	if(val[par] > val[node])
		dpup[node] += dpup[par] ;
	dp[node] += dpup[node] ;
	int sz = adj2[node].size() , sum2 = 0 ;
	for(int i = sz-1 ; i >= 0 ; --i)
	{
		int child = adj2[node][i] ;
		if(child == par)
			continue ;
		dfs3(child , node , sum2) ;
		sum2 += dpdown[child] ;
	}
}

void calc()
{
	for(int i = 1 ; i <= n ; ++i)
		vis[i] = 0 ;
	for(int i = 1 ; i <= n ; ++i)
	{
		if(vis[i])
			continue ;
		dfs2(i , i) ;
		dfs3(i , i , 0) ;
	}
}

char ch[MAX] ;
int X[MAX] , Y[MAX] ;

int main()
{
	ios_base::sync_with_stdio(0) ;
	cin.tie(0) ;
	cin>>n>>q ;
	for(int i = 1 ; i <= n+q-1 ; ++i)
	{
		cin>>ch[i] ;
		if(ch[i] == 'S')
		{
			cin>>X[i]>>Y[i] ;
			adj[X[i]].emplace_back(Y[i] , i) ;
			adj[Y[i]].emplace_back(X[i] , i) ;
		}
		else if(ch[i] == 'Q')
			cin>>X[i]>>Y[i] ;
		else if(ch[i] == 'C')
			cin>>X[i] ;
	}
	dfs(1 , 1) ;
	for(int i = 1 ; i <= n ; ++i)
		dp[i] = 1 ;
	int cnt = 0 ;
	vector<int>v ;
	for(int i = 1 ; i <= n+q-1 ; ++i)
	{
		if(cnt == B)
			calc() , cnt = 0 , v.clear() ;
		if(ch[i] == 'S')
		{
			v.push_back(i) ;
			adj2[X[i]].push_back(Y[i]) ;
			adj2[Y[i]].push_back(X[i]) ;
			cnt++ ;
		}
		else if(ch[i] == 'Q')
		{
			if(check(X[i] , Y[i] , i))
				cout<<"yes\n" ;
			else
				cout<<"no\n" ;
		}
		else if(ch[i] == 'C')
		{
			int ans = dp[X[i]] ;
			for(auto &j : v)
			{
				int a = X[j] , b = Y[j] ;
				if(val[a] != j)
					swap(a , b) ;
				if(check(a , X[i] , i) && (!Ancestor(a , X[i])))
					ans++ ;
				else if(check(b , X[i] , i) && Ancestor(a , X[i]))
					ans++ ;
			}
			cout<<ans<<"\n" ;
		}
	}
	return 0 ;
}

• Subtask 1: 2.5 / 2.5
• Subtask 2: 0 / 2.5
• Subtask 3: 2.5 / 2.5
• Subtask 4: 0 / 2.5
• Subtask 5: 5 / 5
• Subtask 6: 5 / 5
• Subtask 7: 10 / 10
• Subtask 8: 10 / 10
• Subtask 9: 12.5 / 12.5
• Subtask 10: 0 / 12.5
• Subtask 11: 17.5 / 17.5
• Subtask 12: 0 / 17.5