oj.uz

답안 #703423

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
703423 2023-02-27T10:00:33 Z 406 Mousetrap (CEOI17_mousetrap) C++17
100 / 100
 1357 ms 225196 KB 
#include "bits/stdc++.h"
using namespace std;
#define int long long
const int N = 1e6 + 5;
const long long INF = 1ll << 60;
int F[N], n, T, M, ch[N], pr[N], bala[N];
vector<int> adj[N];

void dfs2(int v, int p) {
	for (auto u: adj[v]) if (u != p) {
		bala[u] = bala[v] + ch[v] - 1;
		dfs2(u, v);
	}
}

void dfs(int v, int p) {
	pr[v] = p;
	vector<int> tmp;
	for (auto u: adj[v]) if (u != p) {
		dfs(u, v);
		tmp.push_back(F[u]);
		ch[v]++;
	}
	sort(tmp.rbegin(), tmp.rend());
	if (tmp.size() <= 1)
		F[v] = tmp.size();
	else
		F[v] = tmp[1] + tmp.size();
}

bool check(int O) {
	int m = M;
	int child = -1;
	int cur = 0;
	while (m != T) {
		int d = 0;
		for (auto u: adj[m]) if (u != pr[m] && u != child) {
			int x = F[u] + bala[u] + (m == M);				
			if (x >= O) {
				cur--;
				d--;
			}
		}

		cur++;
		if (cur < 0) return false;

		O += d;
		child = m;
		m = pr[m];
	}
	return O > 0;
}

signed main() {
	ios::sync_with_stdio(0);
	cin.tie(0);
	cin >> n >> T >> M;
	T--, M--;
	for (int i = 1; i < n; i++) {
		int u, v; cin >> u >> v; u--, v--;
		adj[u].push_back(v);
		adj[v].push_back(u);
	}
	if (M == T) {
		cout << 0 << '\n';
		return 0;
	}
	dfs(T, T);
	ch[T] = 1;
	dfs2(T, T);

	for (int i = 0; i < n; i++) {
		sort(adj[i].begin(), adj[i].end(), [&](const int x, const int y) {return F[x] + bala[x] > F[y] + bala[y];});
	}

	int l = 0, r = INF;
	while (r - l > 1) {
		int m = l + r >> 1;
		if (check(m)) r = m;
		else l = m;
	}

	cout << l << '\n';
	return 0;
}

Compilation message

mousetrap.cpp: In function 'int main()':
mousetrap.cpp:79:13: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   79 |   int m = l + r >> 1;
      |           ~~^~~

Subtask #1
20.0 / 20.0

# 결과 실행 시간 메모리 Grader output
1 Correct 14 ms 23764 KB Output is correct
2 Correct 15 ms 23816 KB Output is correct
3 Correct 13 ms 23776 KB Output is correct
4 Correct 14 ms 23756 KB Output is correct
5 Correct 12 ms 23808 KB Output is correct
6 Correct 14 ms 23764 KB Output is correct
7 Correct 12 ms 23764 KB Output is correct
8 Correct 12 ms 23764 KB Output is correct
9 Correct 12 ms 23764 KB Output is correct
10 Correct 12 ms 23812 KB Output is correct

Subtask #2
25.0 / 25.0

# 결과 실행 시간 메모리 Grader output
1 Correct 358 ms 90340 KB Output is correct
2 Correct 292 ms 83684 KB Output is correct
3 Correct 975 ms 92508 KB Output is correct
4 Correct 489 ms 58184 KB Output is correct
5 Correct 982 ms 92624 KB Output is correct
6 Correct 1014 ms 92680 KB Output is correct

Subtask #3
20.0 / 20.0

# 결과 실행 시간 메모리 Grader output
1 Correct 14 ms 23764 KB Output is correct
2 Correct 15 ms 23816 KB Output is correct
3 Correct 13 ms 23776 KB Output is correct
4 Correct 14 ms 23756 KB Output is correct
5 Correct 12 ms 23808 KB Output is correct
6 Correct 14 ms 23764 KB Output is correct
7 Correct 12 ms 23764 KB Output is correct
8 Correct 12 ms 23764 KB Output is correct
9 Correct 12 ms 23764 KB Output is correct
10 Correct 12 ms 23812 KB Output is correct
11 Correct 12 ms 23764 KB Output is correct
12 Correct 14 ms 23892 KB Output is correct
13 Correct 13 ms 23812 KB Output is correct
14 Correct 13 ms 24020 KB Output is correct
15 Correct 16 ms 24008 KB Output is correct
16 Correct 15 ms 23892 KB Output is correct
17 Correct 13 ms 23816 KB Output is correct
18 Correct 12 ms 23816 KB Output is correct
19 Correct 14 ms 23820 KB Output is correct
20 Correct 13 ms 23884 KB Output is correct
21 Correct 12 ms 23892 KB Output is correct
22 Correct 12 ms 23892 KB Output is correct

Subtask #4
35.0 / 35.0

# 결과 실행 시간 메모리 Grader output
1 Correct 14 ms 23764 KB Output is correct
2 Correct 15 ms 23816 KB Output is correct
3 Correct 13 ms 23776 KB Output is correct
4 Correct 14 ms 23756 KB Output is correct
5 Correct 12 ms 23808 KB Output is correct
6 Correct 14 ms 23764 KB Output is correct
7 Correct 12 ms 23764 KB Output is correct
8 Correct 12 ms 23764 KB Output is correct
9 Correct 12 ms 23764 KB Output is correct
10 Correct 12 ms 23812 KB Output is correct
11 Correct 358 ms 90340 KB Output is correct
12 Correct 292 ms 83684 KB Output is correct
13 Correct 975 ms 92508 KB Output is correct
14 Correct 489 ms 58184 KB Output is correct
15 Correct 982 ms 92624 KB Output is correct
16 Correct 1014 ms 92680 KB Output is correct
17 Correct 12 ms 23764 KB Output is correct
18 Correct 14 ms 23892 KB Output is correct
19 Correct 13 ms 23812 KB Output is correct
20 Correct 13 ms 24020 KB Output is correct
21 Correct 16 ms 24008 KB Output is correct
22 Correct 15 ms 23892 KB Output is correct
23 Correct 13 ms 23816 KB Output is correct
24 Correct 12 ms 23816 KB Output is correct
25 Correct 14 ms 23820 KB Output is correct
26 Correct 13 ms 23884 KB Output is correct
27 Correct 12 ms 23892 KB Output is correct
28 Correct 12 ms 23892 KB Output is correct
29 Correct 12 ms 23808 KB Output is correct
30 Correct 389 ms 103568 KB Output is correct
31 Correct 323 ms 103576 KB Output is correct
32 Correct 586 ms 225196 KB Output is correct
33 Correct 399 ms 225172 KB Output is correct
34 Correct 981 ms 105780 KB Output is correct
35 Correct 1042 ms 105728 KB Output is correct
36 Correct 1357 ms 118264 KB Output is correct
37 Correct 1350 ms 118296 KB Output is correct
38 Correct 966 ms 116428 KB Output is correct
39 Correct 945 ms 116428 KB Output is correct
40 Correct 844 ms 116340 KB Output is correct