oj.uz

Submission #585086

# Submission time Handle Problem Language Result Execution time Memory
585086 2022-06-28T09:55:38 Z amunduzbaev Mousetrap (CEOI17_mousetrap) C++17
45 / 100
 807 ms 69312 KB 
#include "bits/stdc++.h"
using namespace std;
 
#define ar array
typedef int64_t ll;
 
const int N = 1e6 + 5;
vector<int> edges[N];
int n, t, m, dp[N], is[N];
int c[N];
 
void dfs(int u, int p = -1){
	is[u] = (u == t), c[u] = -1;
	vector<int> t;
	for(auto x : edges[u]){
		if(x == p) continue;
		dfs(x, u);
		is[u] |= is[x];
		if(!is[x]) t.push_back(x);
		else c[u] = x;
	}
	sort(t.begin(), t.end(), [&](int& i, int& j){
		return dp[i] > dp[j];
	});
	edges[u] = t;
	
	if(t.empty()) dp[u] = 0;
	else {
		dp[u] = t.size();
		if((int)t.size() > 1) dp[u] += dp[t[1]]; 
	}
}
 
signed main(){
	ios::sync_with_stdio(0); cin.tie(0);
	
	cin>>n>>t>>m;
	if(t == m){
		cout<<0<<"\n";
		return 0;
	}
	for(int i=1;i<n;i++){
		int a, b; cin>>a>>b;
		edges[a].push_back(b);
		edges[b].push_back(a);
	}
	
	dfs(m);
	int tot = 0, u = m;
	while(u != t){
		tot += edges[u].size();
		u = c[u];
	}
	auto check = [&](int mx){
		int u = m, pos = 0;
		while(u != t){
			pos++;
			for(auto x : edges[u]){
				if(dp[x] + tot > mx) pos--;
			}
			if(pos < 0) return false;
			u = c[u];
		}
		
		return true;
	};
	
	int l = tot, r = 1e9;
	while(l < r){
		int m = (l + r) >> 1;
		if(check(m)) r = m;
		else l = m + 1;
	}
	
	//~ while(m != t){
		//~ pos++;
		//~ vector<int>& t = edges[m];
		//~ sort(t.begin(), t.end(), [&](int& i, int& j){
			//~ return dp[i] > dp[j];
		//~ });
		
		//~ if(pos >= (int)t.size()){
			//~ pos -= (int)t.size();
			//~ res += (int)t.size();
		//~ } else {
			//~ res += dp[t[pos]] + (int)t.size();
			//~ pos = 1e9;
		//~ }
		//~ m = c[m];
	//~ }
	
	cout<<l<<"\n";
}
 
/*
 
8 7 1
1 2
2 3
3 4
3 5
3 6
4 7
4 8
 
*/

Subtask #1
20.0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 11 ms 23760 KB Output is correct
2 Correct 12 ms 23764 KB Output is correct
3 Correct 14 ms 23820 KB Output is correct
4 Correct 13 ms 23808 KB Output is correct
5 Correct 12 ms 23812 KB Output is correct
6 Correct 13 ms 23768 KB Output is correct
7 Correct 12 ms 23828 KB Output is correct
8 Correct 13 ms 23800 KB Output is correct
9 Correct 12 ms 23812 KB Output is correct
10 Correct 14 ms 23764 KB Output is correct

Subtask #2
25.0 / 25.0

# Verdict Execution time Memory Grader output
1 Correct 299 ms 68172 KB Output is correct
2 Correct 277 ms 63820 KB Output is correct
3 Correct 778 ms 69248 KB Output is correct
4 Correct 368 ms 47288 KB Output is correct
5 Correct 764 ms 69312 KB Output is correct
6 Correct 807 ms 69208 KB Output is correct

Subtask #3
0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 11 ms 23760 KB Output is correct
2 Correct 12 ms 23764 KB Output is correct
3 Correct 14 ms 23820 KB Output is correct
4 Correct 13 ms 23808 KB Output is correct
5 Correct 12 ms 23812 KB Output is correct
6 Correct 13 ms 23768 KB Output is correct
7 Correct 12 ms 23828 KB Output is correct
8 Correct 13 ms 23800 KB Output is correct
9 Correct 12 ms 23812 KB Output is correct
10 Correct 14 ms 23764 KB Output is correct
11 Correct 12 ms 23764 KB Output is correct
12 Correct 14 ms 23764 KB Output is correct
13 Correct 12 ms 23816 KB Output is correct
14 Correct 12 ms 23892 KB Output is correct
15 Correct 12 ms 23892 KB Output is correct
16 Incorrect 14 ms 23804 KB Output isn't correct
17 Halted 0 ms 0 KB -

Subtask #4
0 / 35.0

# Verdict Execution time Memory Grader output
1 Correct 11 ms 23760 KB Output is correct
2 Correct 12 ms 23764 KB Output is correct
3 Correct 14 ms 23820 KB Output is correct
4 Correct 13 ms 23808 KB Output is correct
5 Correct 12 ms 23812 KB Output is correct
6 Correct 13 ms 23768 KB Output is correct
7 Correct 12 ms 23828 KB Output is correct
8 Correct 13 ms 23800 KB Output is correct
9 Correct 12 ms 23812 KB Output is correct
10 Correct 14 ms 23764 KB Output is correct
11 Correct 299 ms 68172 KB Output is correct
12 Correct 277 ms 63820 KB Output is correct
13 Correct 778 ms 69248 KB Output is correct
14 Correct 368 ms 47288 KB Output is correct
15 Correct 764 ms 69312 KB Output is correct
16 Correct 807 ms 69208 KB Output is correct
17 Correct 12 ms 23764 KB Output is correct
18 Correct 14 ms 23764 KB Output is correct
19 Correct 12 ms 23816 KB Output is correct
20 Correct 12 ms 23892 KB Output is correct
21 Correct 12 ms 23892 KB Output is correct
22 Incorrect 14 ms 23804 KB Output isn't correct
23 Halted 0 ms 0 KB -