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Submission #161602

# Submission time Handle Problem Language Result Execution time Memory
161602 2019-11-03T08:53:31 Z amoo_safar Mousetrap (CEOI17_mousetrap) C++14
25 / 100
 1054 ms 94284 KB 
#include <bits/stdc++.h>
 
#define pb push_back
#define F first
#define S second
 
using namespace std;
 
typedef long long ll;
typedef string str;
 
const ll Mod = 1e9 + 7;
const int Maxn = 1e6 + 100;

vector<ll> G[Maxn];
ll dp[Maxn], son[Maxn], m1[Maxn], m2[Maxn];
ll t, m;
vector<ll> V;
bool DFS(ll u, ll p){
	bool res = (u == m), r2;
	ll cnt = 0;
	ll mx = 0;
	ll mx2 = 0;
	
	for(auto adj : G[u]){
		if(adj == p) continue;
		r2 =DFS(adj, u);
		res |= r2;
		if(!r2){
			cnt ++;
			if(dp[adj] > mx){
				mx2 = mx;
				mx = dp[adj];
			} else mx2 = max(mx2, dp[adj]);
		}
	}
	dp[u] = cnt + mx2;
	m2[u] = mx2;
	m1[u] = mx;
	son[u] = cnt;
	if(res){
		V.pb(u);
	}
	return res;
}
ll dp2[Maxn];
int main(){
	ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
	ll n;
	cin >> n >> t >> m;
	ll u, v;
	for(int i = 1; i < n; i++){
		cin >> u >> v;
		G[u].pb(v);
		G[v].pb(u);
	}
	DFS(t, -1);
	
	
	ll sz = V.size();
	dp2[sz-1] = 0;
	ll sm = 0;
	for(int i = sz - 2; i >= 0; i--){
		dp2[i] = min( max(dp2[i + 1], sm + m1[V[i]] + son[V[i]]), 1LL + max(dp2[i + 1], sm + m2[V[i]] + son[V[i]] - 1) );
		sm += son[V[i]];
	}
	
	cout << dp2[0] << '\n';
	
	
	return 0;
}

Subtask #1
0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 24 ms 23928 KB Output is correct
2 Correct 24 ms 23928 KB Output is correct
3 Correct 24 ms 23928 KB Output is correct
4 Correct 25 ms 23932 KB Output is correct
5 Incorrect 25 ms 23928 KB Output isn't correct
6 Halted 0 ms 0 KB -

Subtask #2
25.0 / 25.0

# Verdict Execution time Memory Grader output
1 Correct 491 ms 94284 KB Output is correct
2 Correct 440 ms 87288 KB Output is correct
3 Correct 1043 ms 92640 KB Output is correct
4 Correct 519 ms 58232 KB Output is correct
5 Correct 1048 ms 92824 KB Output is correct
6 Correct 1054 ms 92696 KB Output is correct

Subtask #3
0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 24 ms 23928 KB Output is correct
2 Correct 24 ms 23928 KB Output is correct
3 Correct 24 ms 23928 KB Output is correct
4 Correct 25 ms 23932 KB Output is correct
5 Incorrect 25 ms 23928 KB Output isn't correct
6 Halted 0 ms 0 KB -

Subtask #4
0 / 35.0

# Verdict Execution time Memory Grader output
1 Correct 24 ms 23928 KB Output is correct
2 Correct 24 ms 23928 KB Output is correct
3 Correct 24 ms 23928 KB Output is correct
4 Correct 25 ms 23932 KB Output is correct
5 Incorrect 25 ms 23928 KB Output isn't correct
6 Halted 0 ms 0 KB -