oj.uz

Submission #376320

# Submission time Handle Problem Language Result Execution time Memory
376320 2021-03-11T08:27:28 Z errorgorn Papričice (COCI20_papricice) C++17
110 / 110
 301 ms 37348 KB 
//雪花飄飄北風嘯嘯
//天地一片蒼茫

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/rope>
using namespace std;
using namespace __gnu_pbds;
using namespace __gnu_cxx;
#define ll long long
#define ii pair<ll,ll>
#define iii pair<ii,ll>
#define fi first
#define se second
#define endl '\n'
#define debug(x) cout << #x << " is " << x << endl

#define pub push_back
#define pob pop_back
#define puf push_front
#define pof pop_front
#define lb lower_bound
#define up upper_bound

#define rep(x,start,end) for(auto x=(start)-((start)>(end));x!=(end)-((start)>(end));((start)<(end)?x++:x--))
#define all(x) (x).begin(),(x).end()
#define sz(x) (int)(x).size()

#define indexed_set tree<ll,null_type,less<ll>,rb_tree_tag,tree_order_statistics_node_update>
//change less to less_equal for non distinct pbds, but erase will bug

mt19937 rng(chrono::system_clock::now().time_since_epoch().count());

int n;
vector<int> al[200005];
set<int> s[200005];
int sz[200005];

void dfs_sz(int i,int p){
	sz[i]=1;
	
	for (auto &it:al[i]){
		if (it==p) continue;
		dfs_sz(it,i);
		sz[i]+=sz[it];
	}
}

ll ans=1e9;

ll calc(int i,int j){
	int k=n-i-j;
	int arr[3]={i,j,k};
	sort(arr,arr+3);
	return arr[2]-arr[0];
}

void dfs(int i,int p){
	for (auto &it:al[i]){
		if (it==p) continue;
		
		dfs(it,i);
		
		if (sz(s[it])>sz(s[i])) swap(s[it],s[i]);
		
		for (auto &it:s[it]){
			auto temp=s[i].lb((n-it)/2);
			if (temp!=s[i].begin()){
				ans=min(ans,calc(it,*prev(temp)));
			}
			if (temp!=s[i].end()){
				ans=min(ans,calc(it,*temp));
			}
		}
		
		s[i].insert(all(s[it]));
		
		// auto temp=s[i];
		// for (auto &it:s[it]){
			// s[i].insert(it);
			// for (auto &it2:temp) ans=min(ans,calc(it,it2));
		// }
	}
	
	auto temp=s[i].lb(sz[i]/2);
	if (temp!=s[i].begin()){
		ans=min(ans,calc(sz[i]-*prev(temp),*prev(temp)));
	}
	if (temp!=s[i].end()){
		ans=min(ans,calc(sz[i]-*temp,*temp));
	}
	
	//for (auto &it:s[i]) ans=min(ans,calc(sz[i]-it,it));
	
	s[i].insert(sz[i]);
}

int main(){
	ios::sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0);
	cin.exceptions(ios::badbit | ios::failbit);
	
	cin>>n;
	
	int a,b;
	rep(x,1,n){
		cin>>a>>b;
		al[a].pub(b);
		al[b].pub(a);
	}
	
	dfs_sz(1,-1);
	dfs(1,-1);
	
	cout<<ans<<endl;
}

Subtask #1
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 10 ms 14444 KB Output is correct
2 Correct 12 ms 14444 KB Output is correct
3 Correct 10 ms 14444 KB Output is correct
4 Correct 10 ms 14444 KB Output is correct
5 Correct 10 ms 14444 KB Output is correct

Subtask #2
35.0 / 35.0

# Verdict Execution time Memory Grader output
1 Correct 10 ms 14444 KB Output is correct
2 Correct 12 ms 14444 KB Output is correct
3 Correct 10 ms 14444 KB Output is correct
4 Correct 10 ms 14444 KB Output is correct
5 Correct 10 ms 14444 KB Output is correct
6 Correct 12 ms 14572 KB Output is correct
7 Correct 11 ms 14572 KB Output is correct
8 Correct 11 ms 14572 KB Output is correct
9 Correct 11 ms 14572 KB Output is correct
10 Correct 11 ms 14572 KB Output is correct

Subtask #3
60.0 / 60.0

# Verdict Execution time Memory Grader output
1 Correct 10 ms 14444 KB Output is correct
2 Correct 12 ms 14444 KB Output is correct
3 Correct 10 ms 14444 KB Output is correct
4 Correct 10 ms 14444 KB Output is correct
5 Correct 10 ms 14444 KB Output is correct
6 Correct 12 ms 14572 KB Output is correct
7 Correct 11 ms 14572 KB Output is correct
8 Correct 11 ms 14572 KB Output is correct
9 Correct 11 ms 14572 KB Output is correct
10 Correct 11 ms 14572 KB Output is correct
11 Correct 273 ms 32748 KB Output is correct
12 Correct 285 ms 33516 KB Output is correct
13 Correct 260 ms 32620 KB Output is correct
14 Correct 259 ms 33132 KB Output is correct
15 Correct 301 ms 33516 KB Output is correct
16 Correct 208 ms 31720 KB Output is correct
17 Correct 260 ms 32900 KB Output is correct
18 Correct 234 ms 37348 KB Output is correct
19 Correct 254 ms 33900 KB Output is correct
20 Correct 287 ms 33516 KB Output is correct