oj.uz

답안 #563712

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
563712 2022-05-18T03:38:21 Z ngpin04 Mousetrap (CEOI17_mousetrap) C++14
20 / 100
 267 ms 66748 KB 
#include <bits/stdc++.h>
#define fi first
#define se second
#define mp make_pair
#define TASK ""
#define bit(x) (1LL << (x))
#define getbit(x, i) (((x) >> (i)) & 1)
#define ALL(x) (x).begin(), (x).end() 
using namespace std;
template <typename T1, typename T2> bool mini(T1 &a, T2 b) {
	if (a > b) {a = b; return true;} return false;
}
template <typename T1, typename T2> bool maxi(T1 &a, T2 b) {
	if (a < b) {a = b; return true;} return false;
}
mt19937_64 rd(chrono::steady_clock::now().time_since_epoch().count());

int rand(int l, int r) {
	return l + rd() % (r - l + 1);
}
const int N = 1e6 + 5; 
const int oo = 1e9;
const long long ooo = 1e18;
const int mod = 1e9 + 7; // 998244353;
const long double pi = acos(-1);

vector <int> adj[N];
vector <int> a;

int deg[N];
int par[N];
int dp[N];
int n,t,s;

bool flag[N];

void dfs(int u, int p = -1) {
	par[u] = p;
	for (int v : adj[u]) 
		if (v != p) 
			dfs(v, u);
}

void solve(int u, int p = -1) {
	deg[u] = 0;
	dp[u] = 0;
	for (int v : adj[u]) if (v != p) {
		solve(v, u);
		deg[u]++;
		maxi(dp[u], dp[v]);
	}
	dp[u] += deg[u];
}

bool check(int lim) {
	int tot = 0;
	for (int v : a)
		tot += deg[v];
	if (lim < tot)
		return false;
			
	for (int i = 0, cnt = 0; i < (int) a.size(); i++) {
		int u = a[i];
		int skipped = 0;
		for (int v : adj[u]) 
			if (!flag[v]) 
				skipped += (dp[v] + tot) <= lim;
				 	
		for (int v : adj[u]) 
			if (!flag[v])
				cnt += (dp[v] + tot > lim);
				
		tot -= skipped;
		
		if (cnt > i + 1)
			return false;
			
	}
	return true;
}

int main() {
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	#ifdef ONLINE_JUDGE
	freopen("mousetrap.inp","r",stdin);
	freopen("mousetrap.out","w",stdout);
	#endif
	cin >> n >> t >> s;
	for (int i = 1; i < n; i++) {
		int u,v;
		cin >> u >> v;
		adj[u].push_back(v);
		adj[v].push_back(u);
	}
	
	dfs(s);
	
	while (t != -1) {
		a.push_back(t);
		t = par[t];
	}
	reverse(ALL(a));
	for (int v : a)
		flag[v] = true;
	a.pop_back();
	
		
	for (int u : a) {
		deg[u] = 0;
		for (int v : adj[u]) if (!flag[v]) {
			solve(v, u);
			deg[u]++;
			// cerr << u << " " << v << "\n";
		}
	}
	
	int lo = -1;
	int hi = n;
	while (hi - lo > 1) {
		int mid = (lo + hi) >> 1;
		if (check(mid))
			hi = mid;
		else
			lo = mid;
	}
	
	cout << hi;
	return 0;
}

Subtask #1
20.0 / 20.0

# 결과 실행 시간 메모리 Grader output
1 Correct 12 ms 23764 KB Output is correct
2 Correct 12 ms 23764 KB Output is correct
3 Correct 12 ms 23812 KB Output is correct
4 Correct 12 ms 23748 KB Output is correct
5 Correct 12 ms 23748 KB Output is correct
6 Correct 13 ms 23764 KB Output is correct
7 Correct 13 ms 23752 KB Output is correct
8 Correct 13 ms 23724 KB Output is correct
9 Correct 12 ms 23764 KB Output is correct
10 Correct 13 ms 23812 KB Output is correct

Subtask #2
0 / 25.0

# 결과 실행 시간 메모리 Grader output
1 Incorrect 267 ms 66748 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #3
0 / 20.0

# 결과 실행 시간 메모리 Grader output
1 Correct 12 ms 23764 KB Output is correct
2 Correct 12 ms 23764 KB Output is correct
3 Correct 12 ms 23812 KB Output is correct
4 Correct 12 ms 23748 KB Output is correct
5 Correct 12 ms 23748 KB Output is correct
6 Correct 13 ms 23764 KB Output is correct
7 Correct 13 ms 23752 KB Output is correct
8 Correct 13 ms 23724 KB Output is correct
9 Correct 12 ms 23764 KB Output is correct
10 Correct 13 ms 23812 KB Output is correct
11 Correct 12 ms 23764 KB Output is correct
12 Correct 13 ms 23812 KB Output is correct
13 Correct 12 ms 23820 KB Output is correct
14 Correct 13 ms 23900 KB Output is correct
15 Correct 14 ms 23816 KB Output is correct
16 Incorrect 13 ms 23796 KB Output isn't correct
17 Halted 0 ms 0 KB -

Subtask #4
0 / 35.0

# 결과 실행 시간 메모리 Grader output
1 Correct 12 ms 23764 KB Output is correct
2 Correct 12 ms 23764 KB Output is correct
3 Correct 12 ms 23812 KB Output is correct
4 Correct 12 ms 23748 KB Output is correct
5 Correct 12 ms 23748 KB Output is correct
6 Correct 13 ms 23764 KB Output is correct
7 Correct 13 ms 23752 KB Output is correct
8 Correct 13 ms 23724 KB Output is correct
9 Correct 12 ms 23764 KB Output is correct
10 Correct 13 ms 23812 KB Output is correct
11 Incorrect 267 ms 66748 KB Output isn't correct
12 Halted 0 ms 0 KB -