Submission #447063

#	Time	Username	Problem	Language	Result	Execution time	Memory
447063		Jasiekstrz	Janjetina (COCI21_janjetina)	C++17	110 / 110	1214 ms	113732 KiB

Main

#include<bits/stdc++.h>
#include<ext/pb_ds/assoc_container.hpp>
#include<ext/pb_ds/tree_policy.hpp>
#define fi first
#define se second
using namespace std;
using namespace __gnu_pbds;
const int N=1e5;
typedef tree<pair<int,int>,null_type,less<pair<int,int>>,rb_tree_tag,tree_order_statistics_node_update> ordered_set;
vector<pair<int,int>> e[N+10];
bool vis[N+10];
int siz[N+10];
int dep[N+10];
int par[N+10];
int mx[N+10];
ordered_set os;
ordered_set st[N+10];
priority_queue<pair<int,int>> pq;
void dfs_size(int x,int p)
{
	siz[x]=1;
	for(auto v:e[x])
	{
		if(v.fi!=p && !vis[v.fi])
		{
			dfs_size(v.fi,x);
			siz[x]+=siz[v.fi];
		}
	}
	return;
}
int find_centro(int x,int p,int size_all)
{
	for(auto v:e[x])
	{
		if(v.fi!=p && !vis[v.fi])
		{
			int tmp=find_centro(v.fi,x,size_all);
			if(tmp!=-1)
				return tmp;
		}
	}
	if(2*siz[x]>=size_all)
		return x;
	return -1;
}
long long centro(int x,int k)
{
	dfs_size(x,0);
	x=find_centro(x,0,siz[x]);
	dfs_size(x,0);
	//cerr<<"centro "<<x<<"\n";
	vis[x]=true;
	dep[x]=0;
	mx[x]=0;
	os.clear();
	while(!pq.empty())
		pq.pop();
	os.insert({0,x});
	for(auto [v,c]:e[x])
	{
		if(!vis[v])
		{
			dep[v]=1;
			mx[v]=c;
			par[v]=v;
			st[v].clear();
			pq.emplace(-mx[v],v);
		}
	}
	long long ans=0;
	while(!pq.empty())
	{
		int y=pq.top().se;
		pq.pop();
		int d=mx[y]-dep[y]-k;
		//cerr<<y<<" "<<d<<"\n";
		ans+=os.order_of_key({d+1,0})-st[par[y]].order_of_key({d+1,0});
		os.insert({dep[y],y});
		st[par[y]].insert({dep[y],y});
		for(auto [v,c]:e[y])
		{
			if(!vis[v] && siz[v]<siz[y])
			{
				mx[v]=max(mx[y],c);
				dep[v]=dep[y]+1;
				par[v]=par[y];
				pq.emplace(-mx[v],v);
			}
		}
	}
	for(auto [v,c]:e[x])
	{
		if(!vis[v])
			ans+=centro(v,k);
	}
	return ans;
}
int main()
{
	ios_base::sync_with_stdio(false);
	cin.tie(NULL);
	cout.tie(NULL);
	int n,k;
	cin>>n>>k;
	for(int i=1;i<n;i++)
	{
		int a,b,c;
		cin>>a>>b>>c;
		e[a].emplace_back(b,c);
		e[b].emplace_back(a,c);
	}
	cout<<2*centro(1,k)<<"\n";
	return 0;
}

• Subtask 1: 15 / 15
• Subtask 2: 35 / 35
• Subtask 3: 60 / 60