Submission #735587

#	Time	Username	Problem	Language	Result	Execution time	Memory
735587		Koful123	Papričice (COCI20_papricice)	C++17	110 / 110	428 ms	29152 KiB

papricice

#include <bits/stdc++.h>
using namespace std;
#define int long long
#define endl "\n"
#define ff first
#define ss second
#define pb push_back
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()

const int N = 2e5 + 5;
int ans = 1e18,n;
vector<int> adj[N],sz(N);
multiset<int> other,anc;

void calc(int node,int p){
	sz[node] = 1;
	for(int go : adj[node]){
		if(go == p) continue;
		calc(go,node);
		sz[node] = sz[go] + sz[node];
	}
}

int search(multiset<int> &s,int x,int ty){
	int res = 1e18,cur = x;
	if(!ty) cur = (n - x) / 2 + x;
	else cur = (n - x) / 2;
	auto it = s.upper_bound(cur);
	if(ty){
		if(it != s.end()){
			vector<int> tmp = {x,n - x - *it,*it};
			sort(tmp.begin(), tmp.end());
			res = min(res,tmp[2] - tmp[0]);
		}
		if(it != s.begin()){
			vector<int> tmp = {x,n - *prev(it) - x,*prev(it)};
			sort(tmp.begin(), tmp.end());
			res = min(res,tmp[2] - tmp[0]);
		}
		return res;		
	}

	if(it != s.end()){
		vector<int> tmp = {x,n - *it,*it - x};
		sort(tmp.begin(), tmp.end());
		res = min(res,tmp[2] - tmp[0]);
	}
	if(it != s.begin()){
		vector<int> tmp = {x,n - *prev(it),*prev(it) - x};
		sort(tmp.begin(), tmp.end());
		res = min(res,tmp[2] - tmp[0]);
	}
	return res;
}

void dfs(int node,int p){
	ans = min({ans,search(anc,sz[node],0),search(other,sz[node],1)});
	anc.insert(sz[node]);
	for(int go : adj[node]){
		if(go == p) continue;
		dfs(go,node);
	}
	anc.erase(anc.find(sz[node]));
	other.insert(sz[node]);
}	

void solve(){

	cin >> n;
	for(int i = 1; i < n; i++){
		int a,b; cin >> a >> b;
		adj[a].push_back(b);
		adj[b].push_back(a);
	}

	calc(1,0);
	dfs(1,0);

	cout << ans << endl;
}
 
signed main(){ 
 
	ios::sync_with_stdio(0);
	cin.tie(0);
 
	int t = 1;
//	cin >> t;
 
	while(t--)
		solve();
 	
	return 0;
}

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