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Submission #941977

# Submission time Handle Problem Language Result Execution time Memory
941977 2024-03-09T21:54:46 Z andrei_c1 Cat in a tree (BOI17_catinatree) C++17
100 / 100
 188 ms 50508 KB 
#include <bits/stdc++.h>
using namespace std;

const int kN = 2e5;
const int kLog = 20;
const int kInf = 1e9;

int dep[kN], tin[kN];
vector<int> adj[kN], rmq[kLog];

void dfs(int u, int p = -1) {
	tin[u] = rmq[0].size();
	rmq[0].emplace_back(u);
	for(const auto &v: adj[u]) if(v != p) {
		dep[v] = dep[u] + 1;
		dfs(v, u);
		rmq[0].emplace_back(u);
	}
}

int minNode(int u, int v) {
	if(dep[u] < dep[v]) return u;
	return v;
}

int lca(int u, int v) {
	int l = tin[u], r = tin[v];
	if(l > r) swap(l, r);
	int lg = __lg(r - l + 1);
	return minNode(rmq[lg][l], rmq[lg][r - (1 << lg) + 1]);
}

int dist(int u, int v) {
	return dep[u] + dep[v] - 2 * dep[lca(u, v)];
}

void minSelf(int &x, int y) {
	if(y < x) {
		x = y;
	}
}

int sz[kN];
bitset<kN> rem;

void findSizes(int u, int p = -1) {
	sz[u] = 1;
	for(const auto &v: adj[u]) if(!rem[v] && v != p) {
		findSizes(v, u);
		sz[u] += sz[v];
	}
}

int findCentroid(int u, int desired, int p = -1) {
	for(const auto &v: adj[u]) if(!rem[v] && v != p && sz[v] > desired) {
		return findCentroid(v, desired, u);
	}
	return u;
}

int up[kN], best[kN];

void buildTree(int u, int p = -1) {
	findSizes(u);
	int c = findCentroid(u, sz[u] >> 1);
	rem[c] = true;
	up[c] = p;
	for(const auto &v: adj[c]) if(!rem[v]) {
		buildTree(v, c);
	}
}

int findClosest(int u) {
	int res = kInf, v = u;
	while(v != -1) {
		minSelf(res, best[v] + dist(u, v));
		v = up[v];
	}
	return res;
}

void updateClosest(int u) {
	int v = u;
	while(v != -1) {
		minSelf(best[v], dist(u, v));
		v = up[v];
	}
}

int main() {
	cin.tie(nullptr)->sync_with_stdio(false);
	int n, d;
	cin >> n >> d;
	for(int i = 1; i < n; i++) {
		int x;
		cin >> x;
		adj[x].emplace_back(i);
		adj[i].emplace_back(x);
	}
	rmq[0].reserve(n << 1);
	dfs(0);
	for(int i = 1; (1 << i) < n << 1; i++) {
		for(int j = 0; j + (1 << i) - 1 < 2 * n - 1; j++) {
			rmq[i].emplace_back(minNode(rmq[i - 1][j], rmq[i - 1][j + (1 << (i - 1))]));
		}
	}
	vector<int> ord(n);
	iota(ord.begin(), ord.end(), 0);
	sort(ord.begin(), ord.end(), [&] (int u, int v) {
		return dep[u] > dep[v];
	});
	fill(best, best + n, kInf);
	fill(up, up + n, -1);
	buildTree(0);
	int ans = 0;
	for(const auto &u: ord) {
		int closest = findClosest(u);
		if(closest >= d) {
			ans++;
			updateClosest(u);
		}
	}
	cout << ans;
	return 0;
}

Subtask #1
11.0 / 11.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 8540 KB Output is correct
2 Correct 1 ms 8540 KB Output is correct
3 Correct 1 ms 8540 KB Output is correct
4 Correct 1 ms 8540 KB Output is correct
5 Correct 1 ms 8540 KB Output is correct
6 Correct 1 ms 8540 KB Output is correct
7 Correct 2 ms 8540 KB Output is correct
8 Correct 2 ms 8540 KB Output is correct
9 Correct 1 ms 8540 KB Output is correct
10 Correct 1 ms 8540 KB Output is correct
11 Correct 2 ms 8540 KB Output is correct
12 Correct 1 ms 8540 KB Output is correct
13 Correct 2 ms 8540 KB Output is correct
14 Correct 1 ms 8540 KB Output is correct
15 Correct 1 ms 8540 KB Output is correct
16 Correct 1 ms 8540 KB Output is correct
17 Correct 2 ms 8540 KB Output is correct
18 Correct 3 ms 8540 KB Output is correct
19 Correct 1 ms 8540 KB Output is correct
20 Correct 1 ms 8540 KB Output is correct

Subtask #2
40.0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 8540 KB Output is correct
2 Correct 1 ms 8540 KB Output is correct
3 Correct 1 ms 8540 KB Output is correct
4 Correct 1 ms 8540 KB Output is correct
5 Correct 1 ms 8540 KB Output is correct
6 Correct 1 ms 8540 KB Output is correct
7 Correct 2 ms 8540 KB Output is correct
8 Correct 2 ms 8540 KB Output is correct
9 Correct 1 ms 8540 KB Output is correct
10 Correct 1 ms 8540 KB Output is correct
11 Correct 2 ms 8540 KB Output is correct
12 Correct 1 ms 8540 KB Output is correct
13 Correct 2 ms 8540 KB Output is correct
14 Correct 1 ms 8540 KB Output is correct
15 Correct 1 ms 8540 KB Output is correct
16 Correct 1 ms 8540 KB Output is correct
17 Correct 2 ms 8540 KB Output is correct
18 Correct 3 ms 8540 KB Output is correct
19 Correct 1 ms 8540 KB Output is correct
20 Correct 1 ms 8540 KB Output is correct
21 Correct 2 ms 8796 KB Output is correct
22 Correct 2 ms 8540 KB Output is correct
23 Correct 2 ms 8540 KB Output is correct
24 Correct 2 ms 8540 KB Output is correct
25 Correct 2 ms 8796 KB Output is correct
26 Correct 2 ms 8796 KB Output is correct
27 Correct 2 ms 8796 KB Output is correct
28 Correct 2 ms 8896 KB Output is correct
29 Correct 2 ms 9048 KB Output is correct
30 Correct 2 ms 8796 KB Output is correct
31 Correct 3 ms 8796 KB Output is correct
32 Correct 2 ms 8796 KB Output is correct
33 Correct 2 ms 8796 KB Output is correct
34 Correct 2 ms 8796 KB Output is correct
35 Correct 3 ms 8796 KB Output is correct
36 Correct 2 ms 8892 KB Output is correct
37 Correct 2 ms 8796 KB Output is correct
38 Correct 2 ms 8796 KB Output is correct
39 Correct 3 ms 8796 KB Output is correct
40 Correct 2 ms 8796 KB Output is correct

Subtask #3
49.0 / 49.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 8540 KB Output is correct
2 Correct 1 ms 8540 KB Output is correct
3 Correct 1 ms 8540 KB Output is correct
4 Correct 1 ms 8540 KB Output is correct
5 Correct 1 ms 8540 KB Output is correct
6 Correct 1 ms 8540 KB Output is correct
7 Correct 2 ms 8540 KB Output is correct
8 Correct 2 ms 8540 KB Output is correct
9 Correct 1 ms 8540 KB Output is correct
10 Correct 1 ms 8540 KB Output is correct
11 Correct 2 ms 8540 KB Output is correct
12 Correct 1 ms 8540 KB Output is correct
13 Correct 2 ms 8540 KB Output is correct
14 Correct 1 ms 8540 KB Output is correct
15 Correct 1 ms 8540 KB Output is correct
16 Correct 1 ms 8540 KB Output is correct
17 Correct 2 ms 8540 KB Output is correct
18 Correct 3 ms 8540 KB Output is correct
19 Correct 1 ms 8540 KB Output is correct
20 Correct 1 ms 8540 KB Output is correct
21 Correct 2 ms 8796 KB Output is correct
22 Correct 2 ms 8540 KB Output is correct
23 Correct 2 ms 8540 KB Output is correct
24 Correct 2 ms 8540 KB Output is correct
25 Correct 2 ms 8796 KB Output is correct
26 Correct 2 ms 8796 KB Output is correct
27 Correct 2 ms 8796 KB Output is correct
28 Correct 2 ms 8896 KB Output is correct
29 Correct 2 ms 9048 KB Output is correct
30 Correct 2 ms 8796 KB Output is correct
31 Correct 3 ms 8796 KB Output is correct
32 Correct 2 ms 8796 KB Output is correct
33 Correct 2 ms 8796 KB Output is correct
34 Correct 2 ms 8796 KB Output is correct
35 Correct 3 ms 8796 KB Output is correct
36 Correct 2 ms 8892 KB Output is correct
37 Correct 2 ms 8796 KB Output is correct
38 Correct 2 ms 8796 KB Output is correct
39 Correct 3 ms 8796 KB Output is correct
40 Correct 2 ms 8796 KB Output is correct
41 Correct 87 ms 42720 KB Output is correct
42 Correct 78 ms 25712 KB Output is correct
43 Correct 80 ms 25708 KB Output is correct
44 Correct 74 ms 25672 KB Output is correct
45 Correct 70 ms 25668 KB Output is correct
46 Correct 185 ms 44272 KB Output is correct
47 Correct 188 ms 44264 KB Output is correct
48 Correct 178 ms 44364 KB Output is correct
49 Correct 168 ms 44256 KB Output is correct
50 Correct 51 ms 25928 KB Output is correct
51 Correct 49 ms 25992 KB Output is correct
52 Correct 47 ms 26188 KB Output is correct
53 Correct 149 ms 45060 KB Output is correct
54 Correct 123 ms 45044 KB Output is correct
55 Correct 123 ms 45440 KB Output is correct
56 Correct 2 ms 9052 KB Output is correct
57 Correct 14 ms 13288 KB Output is correct
58 Correct 73 ms 31236 KB Output is correct
59 Correct 166 ms 50508 KB Output is correct
60 Correct 83 ms 43660 KB Output is correct
61 Correct 121 ms 42540 KB Output is correct