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Submission #828363

# Submission time Handle Problem Language Result Execution time Memory
828363 2023-08-17T08:55:06 Z serifefedartar Cat in a tree (BOI17_catinatree) C++17
51 / 100
 1000 ms 31908 KB 
#include <bits/stdc++.h>
using namespace std;
 
#define fast ios::sync_with_stdio(0);cin.tie(0);
typedef long long ll;
#define f first
#define s second
#define MOD 998244353
#define LOGN 18
#define MAXN 200005

vector<vector<int>> graph;
vector<int> par, sz, nearest;
int up[LOGN][MAXN], depth[MAXN];
bool marked[MAXN];

void dfs(int node, int parent) {
	for (auto u : graph[node]) {
		if (u == parent)
			continue;
		depth[u] = depth[node] + 1;
		up[0][u] = node;
		for (int i = 1; i < LOGN; i++)
			up[i][u] = up[i-1][up[i-1][u]];
		dfs(u, node);
	}
}

int find(int node, int k) {
	for (int i = 0; i < LOGN; i++) {
		if ((1<<i) & k)
			node = up[i][node];
	}
	return node;
}

int lca(int a, int b) {
	if (depth[b] > depth[a])
		swap(a, b);
	a = find(a, depth[a] - depth[b]);
	if (a == b)
		return a;
	for (int i = LOGN-1; i >= 0; i--) {
		if (up[i][a] != up[i][b]) {
			a = up[i][a];
			b = up[i][b];
		}
	}
	return up[0][a];
}

int dist(int a, int b) {
	return depth[a] + depth[b] - 2*depth[lca(a, b)];
}
	
int get_sz(int node, int parent) {
	for (auto u : graph[node]) {
		if (u == parent || marked[u])
			continue;
		sz[node] += get_sz(u, node);
	}
	return sz[node];
}

int find_centro(int node, int parent, int n) {
	for (auto u : graph[node]) {
		if (u != parent && !marked[u] && sz[u] * 2 > n)
			return find_centro(u, node, n);
	}
	return node;
}

void decompose(int node, int parent) {
	int n = get_sz(node, parent);
	int centro = find_centro(node, node, n);

	par[centro] = parent;
	marked[centro] = true;
	for (auto u : graph[centro]) {
		if (!marked[u] && u != parent)
			decompose(u, centro);
	}
}

int main() {
	int N, D;
	cin >> N >> D;

	graph = vector<vector<int>>(N, vector<int>());
	nearest = vector<int>(N, 1e9);
	par = vector<int>(N, -1);
	sz = vector<int>(N, 1);
	for (int i = 1; i < N; i++) {
		int x; cin >> x;
		graph[x].push_back(i);
		graph[i].push_back(x);
	}
	for (int i = 0; i < LOGN; i++)
		up[i][0] = 0;
	dfs(0, 0);
	decompose(0, -1);

	vector<pair<int,int>> order;
	for (int i = 0; i < N; i++)
		order.push_back({depth[i], i});
	sort(order.rbegin(), order.rend());

	int ans = 0;
	for (auto u : order) {
		int node = u.s;
		int now = node;
		int mn_dist = 1e9;
		while (now != -1) {
			mn_dist = min(mn_dist, dist(node, now) + nearest[now]);
			now = par[now];
		}

		if (mn_dist >= D) {
			ans++;
			int now = node;
			while (now != -1) {
				nearest[now] = min(nearest[now], dist(node, now));
				now = par[now];
			}
		}
	}
	cout << ans << "\n";
}

Subtask #1
11.0 / 11.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 340 KB Output is correct
2 Correct 0 ms 340 KB Output is correct
3 Correct 0 ms 388 KB Output is correct
4 Correct 0 ms 340 KB Output is correct
5 Correct 0 ms 340 KB Output is correct
6 Correct 0 ms 340 KB Output is correct
7 Correct 0 ms 340 KB Output is correct
8 Correct 0 ms 340 KB Output is correct
9 Correct 0 ms 340 KB Output is correct
10 Correct 0 ms 340 KB Output is correct
11 Correct 0 ms 340 KB Output is correct
12 Correct 0 ms 340 KB Output is correct
13 Correct 0 ms 340 KB Output is correct
14 Correct 0 ms 340 KB Output is correct
15 Correct 0 ms 340 KB Output is correct
16 Correct 0 ms 340 KB Output is correct
17 Correct 0 ms 340 KB Output is correct
18 Correct 0 ms 340 KB Output is correct
19 Correct 1 ms 340 KB Output is correct
20 Correct 0 ms 340 KB Output is correct

Subtask #2
40.0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 340 KB Output is correct
2 Correct 0 ms 340 KB Output is correct
3 Correct 0 ms 388 KB Output is correct
4 Correct 0 ms 340 KB Output is correct
5 Correct 0 ms 340 KB Output is correct
6 Correct 0 ms 340 KB Output is correct
7 Correct 0 ms 340 KB Output is correct
8 Correct 0 ms 340 KB Output is correct
9 Correct 0 ms 340 KB Output is correct
10 Correct 0 ms 340 KB Output is correct
11 Correct 0 ms 340 KB Output is correct
12 Correct 0 ms 340 KB Output is correct
13 Correct 0 ms 340 KB Output is correct
14 Correct 0 ms 340 KB Output is correct
15 Correct 0 ms 340 KB Output is correct
16 Correct 0 ms 340 KB Output is correct
17 Correct 0 ms 340 KB Output is correct
18 Correct 0 ms 340 KB Output is correct
19 Correct 1 ms 340 KB Output is correct
20 Correct 0 ms 340 KB Output is correct
21 Correct 3 ms 724 KB Output is correct
22 Correct 1 ms 468 KB Output is correct
23 Correct 1 ms 468 KB Output is correct
24 Correct 1 ms 468 KB Output is correct
25 Correct 1 ms 468 KB Output is correct
26 Correct 1 ms 468 KB Output is correct
27 Correct 1 ms 468 KB Output is correct
28 Correct 1 ms 596 KB Output is correct
29 Correct 1 ms 596 KB Output is correct
30 Correct 1 ms 596 KB Output is correct
31 Correct 1 ms 596 KB Output is correct
32 Correct 1 ms 596 KB Output is correct
33 Correct 1 ms 596 KB Output is correct
34 Correct 1 ms 596 KB Output is correct
35 Correct 1 ms 596 KB Output is correct
36 Correct 1 ms 596 KB Output is correct
37 Correct 1 ms 596 KB Output is correct
38 Correct 2 ms 596 KB Output is correct
39 Correct 2 ms 596 KB Output is correct
40 Correct 4 ms 724 KB Output is correct

Subtask #3
0 / 49.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 340 KB Output is correct
2 Correct 0 ms 340 KB Output is correct
3 Correct 0 ms 388 KB Output is correct
4 Correct 0 ms 340 KB Output is correct
5 Correct 0 ms 340 KB Output is correct
6 Correct 0 ms 340 KB Output is correct
7 Correct 0 ms 340 KB Output is correct
8 Correct 0 ms 340 KB Output is correct
9 Correct 0 ms 340 KB Output is correct
10 Correct 0 ms 340 KB Output is correct
11 Correct 0 ms 340 KB Output is correct
12 Correct 0 ms 340 KB Output is correct
13 Correct 0 ms 340 KB Output is correct
14 Correct 0 ms 340 KB Output is correct
15 Correct 0 ms 340 KB Output is correct
16 Correct 0 ms 340 KB Output is correct
17 Correct 0 ms 340 KB Output is correct
18 Correct 0 ms 340 KB Output is correct
19 Correct 1 ms 340 KB Output is correct
20 Correct 0 ms 340 KB Output is correct
21 Correct 3 ms 724 KB Output is correct
22 Correct 1 ms 468 KB Output is correct
23 Correct 1 ms 468 KB Output is correct
24 Correct 1 ms 468 KB Output is correct
25 Correct 1 ms 468 KB Output is correct
26 Correct 1 ms 468 KB Output is correct
27 Correct 1 ms 468 KB Output is correct
28 Correct 1 ms 596 KB Output is correct
29 Correct 1 ms 596 KB Output is correct
30 Correct 1 ms 596 KB Output is correct
31 Correct 1 ms 596 KB Output is correct
32 Correct 1 ms 596 KB Output is correct
33 Correct 1 ms 596 KB Output is correct
34 Correct 1 ms 596 KB Output is correct
35 Correct 1 ms 596 KB Output is correct
36 Correct 1 ms 596 KB Output is correct
37 Correct 1 ms 596 KB Output is correct
38 Correct 2 ms 596 KB Output is correct
39 Correct 2 ms 596 KB Output is correct
40 Correct 4 ms 724 KB Output is correct
41 Correct 110 ms 29776 KB Output is correct
42 Correct 157 ms 15812 KB Output is correct
43 Correct 137 ms 15808 KB Output is correct
44 Correct 122 ms 15928 KB Output is correct
45 Correct 114 ms 15832 KB Output is correct
46 Correct 335 ms 31060 KB Output is correct
47 Correct 328 ms 30992 KB Output is correct
48 Correct 318 ms 31088 KB Output is correct
49 Correct 314 ms 31008 KB Output is correct
50 Correct 84 ms 16168 KB Output is correct
51 Correct 92 ms 16172 KB Output is correct
52 Correct 73 ms 16204 KB Output is correct
53 Correct 206 ms 31908 KB Output is correct
54 Correct 206 ms 31848 KB Output is correct
55 Correct 207 ms 31836 KB Output is correct
56 Correct 6 ms 852 KB Output is correct
57 Correct 613 ms 5344 KB Output is correct
58 Execution timed out 1090 ms 21660 KB Time limit exceeded
59 Halted 0 ms 0 KB -