Submission #894627

#	Time	Username	Problem	Language	Result	Execution time	Memory
894627		amirhoseinfar1385	Capital City (JOI20_capital_city)	C++17	100 / 100	480 ms	40112 KiB

capital_city

#include<bits/stdc++.h>
using namespace std;
const int maxn=200000+10,K=200000+10;
vector<int>adj[maxn],allc[K];
int n,k,val[maxn],sz[maxn],part[maxn],visc[K],vis[maxn],now[maxn],rishe,res;

void calsz(int u,int par=0){
	now[u]=rishe;
	part[u]=par;
	visc[val[u]]=0;
	sz[u]=1;
	for(auto x:adj[u]){
		if(vis[x]==0&&x!=par){
			calsz(x,u);
			sz[u]+=sz[x];
		}
	}
}

int findcen(int u,int su,int par=0){
	for(auto x:adj[u]){
		if(vis[x]==0&&x!=par&&sz[x]*2>su){
			return findcen(x,su,u);
		}
	}
	return u;
}

void solve(int u){
	if(now[u]==-rishe){
		return ;
	}
	if(now[u]!=rishe){
		res=n+2;
		return ;
	}
	if(visc[val[u]]==0){
		res++;
		visc[val[u]]=1;
		for(auto x:allc[val[u]]){
			solve(x);
			if(res>n){
				return ;
			}
		}
	}
	now[u]=-rishe;
	solve(part[u]);
}

int cent(int u){
	int ret=n+1;
	calsz(u);
	int v=findcen(u,sz[u]);
	rishe=v;
	calsz(v,v);
	res=0;
	solve(v);
	ret=min(ret,res);
	vis[v]=1;
	for(auto x:adj[v]){
		if(vis[x]==0){
			ret=min(ret,cent(x));
		}
	}
	return ret;
}

int main(){
	ios::sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0);
	cin>>n>>k;
	for(int i=0;i<n-1;i++){
		int u,v;
		cin>>u>>v;
		adj[u].push_back(v);
		adj[v].push_back(u);
	}
	for(int i=1;i<=n;i++){
		cin>>val[i];
		allc[val[i]].push_back(i);
	}
	cout<<(cent(1)-1)<<endl;
}

• Subtask 1: 1 / 1
• Subtask 2: 10 / 10
• Subtask 3: 30 / 30
• Subtask 4: 59 / 59