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Submission #870214

# Submission time Handle Problem Language Result Execution time Memory
870214 2023-11-07T08:50:02 Z NotLinux Papričice (COCI20_papricice) C++17
110 / 110
 226 ms 31076 KB 
#include <bits/stdc++.h>
using namespace std;
#define int long long
const int N = 2e5 + 7;
int n,ans = 1e18 + 7,subt[N];
vector < int > tree[N];
multiset < int > path , notpath;
inline int eval(int a , int b , int c){
	return max({abs(a-b) , abs(a-c) , abs(b-c)});
}
inline vector < int > closest_set(int tar , multiset < int > &ste){
	vector < int > ret;
	auto hi = ste.lower_bound(tar);
	auto lo = --ste.lower_bound(tar);
	if(hi != ste.end())ret.push_back(*hi);
	if(hi != ste.begin())ret.push_back(*lo);
	return ret;
}
inline void dfs0(int node , int past){
	subt[node] = 1;
	for(auto itr : tree[node]){
		if(itr != past){
			dfs0(itr,node);
			subt[node] += subt[itr];
		}
	}
}
inline void dfs1(int node , int past){
	if(path.size()){
		for(auto cand : closest_set((n+subt[node])/2 , path)){
			ans = min(ans , eval(n-cand,cand-subt[node],subt[node]));
		}
	}
	if(notpath.size()){
		for(auto cand : closest_set((n-subt[node])/2 , notpath)){
			ans = min(ans , eval(n-cand-subt[node],cand,subt[node]));
		}
	}
	path.insert(subt[node]);
	for(auto itr : tree[node]){
		if(itr != past){
			dfs1(itr,node);
		}
	}
	path.erase(path.find(subt[node]));
	notpath.insert(subt[node]);
}
void solve(){
	cin >> n;
	for(int i = 1;i<n;i++){
		int u,v;cin >> u >> v;
		tree[u].push_back(v);
		tree[v].push_back(u);
	}
	//precalc : subtree size
	dfs0(1,0);
	dfs1(1,0);
	cout << ans << endl;
}
signed main(){
	ios_base::sync_with_stdio(0);cin.tie(0);
	int testcase = 1;//cin >> testcase;
	while(testcase--)solve();
}

Subtask #1
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 4956 KB Output is correct
2 Correct 1 ms 4956 KB Output is correct
3 Correct 1 ms 4956 KB Output is correct
4 Correct 1 ms 4956 KB Output is correct
5 Correct 1 ms 4956 KB Output is correct

Subtask #2
35.0 / 35.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 4956 KB Output is correct
2 Correct 1 ms 4956 KB Output is correct
3 Correct 1 ms 4956 KB Output is correct
4 Correct 1 ms 4956 KB Output is correct
5 Correct 1 ms 4956 KB Output is correct
6 Correct 2 ms 5212 KB Output is correct
7 Correct 2 ms 5208 KB Output is correct
8 Correct 2 ms 5212 KB Output is correct
9 Correct 2 ms 5208 KB Output is correct
10 Correct 2 ms 5212 KB Output is correct

Subtask #3
60.0 / 60.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 4956 KB Output is correct
2 Correct 1 ms 4956 KB Output is correct
3 Correct 1 ms 4956 KB Output is correct
4 Correct 1 ms 4956 KB Output is correct
5 Correct 1 ms 4956 KB Output is correct
6 Correct 2 ms 5212 KB Output is correct
7 Correct 2 ms 5208 KB Output is correct
8 Correct 2 ms 5212 KB Output is correct
9 Correct 2 ms 5208 KB Output is correct
10 Correct 2 ms 5212 KB Output is correct
11 Correct 166 ms 25996 KB Output is correct
12 Correct 181 ms 25864 KB Output is correct
13 Correct 175 ms 26572 KB Output is correct
14 Correct 158 ms 26132 KB Output is correct
15 Correct 189 ms 25820 KB Output is correct
16 Correct 142 ms 25680 KB Output is correct
17 Correct 196 ms 25864 KB Output is correct
18 Correct 226 ms 31076 KB Output is correct
19 Correct 168 ms 26260 KB Output is correct
20 Correct 187 ms 25944 KB Output is correct