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Submission #941976

# Submission time Handle Problem Language Result Execution time Memory
941976 2024-03-09T21:54:02 Z andrei_c1 Cat in a tree (BOI17_catinatree) C++17
100 / 100
 206 ms 52548 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];
	});
	for(int i = 0; i < n; i++) {
		best[i] = kInf;
		up[i] = -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 2 ms 8540 KB Output is correct
3 Correct 2 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 1 ms 8540 KB Output is correct
8 Correct 2 ms 8536 KB Output is correct
9 Correct 2 ms 8536 KB Output is correct
10 Correct 2 ms 8540 KB Output is correct
11 Correct 1 ms 8540 KB Output is correct
12 Correct 1 ms 8540 KB Output is correct
13 Correct 2 ms 8584 KB Output is correct
14 Correct 1 ms 8540 KB Output is correct
15 Correct 2 ms 8540 KB Output is correct
16 Correct 2 ms 8540 KB Output is correct
17 Correct 2 ms 8540 KB Output is correct
18 Correct 2 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 2 ms 8540 KB Output is correct
3 Correct 2 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 1 ms 8540 KB Output is correct
8 Correct 2 ms 8536 KB Output is correct
9 Correct 2 ms 8536 KB Output is correct
10 Correct 2 ms 8540 KB Output is correct
11 Correct 1 ms 8540 KB Output is correct
12 Correct 1 ms 8540 KB Output is correct
13 Correct 2 ms 8584 KB Output is correct
14 Correct 1 ms 8540 KB Output is correct
15 Correct 2 ms 8540 KB Output is correct
16 Correct 2 ms 8540 KB Output is correct
17 Correct 2 ms 8540 KB Output is correct
18 Correct 2 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 8792 KB Output is correct
27 Correct 2 ms 8796 KB Output is correct
28 Correct 2 ms 8796 KB Output is correct
29 Correct 3 ms 8796 KB Output is correct
30 Correct 2 ms 8796 KB Output is correct
31 Correct 2 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 2 ms 8796 KB Output is correct
36 Correct 2 ms 8796 KB Output is correct
37 Correct 2 ms 8792 KB Output is correct
38 Correct 2 ms 8792 KB Output is correct
39 Correct 2 ms 8796 KB Output is correct
40 Correct 3 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 2 ms 8540 KB Output is correct
3 Correct 2 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 1 ms 8540 KB Output is correct
8 Correct 2 ms 8536 KB Output is correct
9 Correct 2 ms 8536 KB Output is correct
10 Correct 2 ms 8540 KB Output is correct
11 Correct 1 ms 8540 KB Output is correct
12 Correct 1 ms 8540 KB Output is correct
13 Correct 2 ms 8584 KB Output is correct
14 Correct 1 ms 8540 KB Output is correct
15 Correct 2 ms 8540 KB Output is correct
16 Correct 2 ms 8540 KB Output is correct
17 Correct 2 ms 8540 KB Output is correct
18 Correct 2 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 8792 KB Output is correct
27 Correct 2 ms 8796 KB Output is correct
28 Correct 2 ms 8796 KB Output is correct
29 Correct 3 ms 8796 KB Output is correct
30 Correct 2 ms 8796 KB Output is correct
31 Correct 2 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 2 ms 8796 KB Output is correct
36 Correct 2 ms 8796 KB Output is correct
37 Correct 2 ms 8792 KB Output is correct
38 Correct 2 ms 8792 KB Output is correct
39 Correct 2 ms 8796 KB Output is correct
40 Correct 3 ms 8796 KB Output is correct
41 Correct 81 ms 43136 KB Output is correct
42 Correct 80 ms 26184 KB Output is correct
43 Correct 77 ms 26220 KB Output is correct
44 Correct 77 ms 26068 KB Output is correct
45 Correct 73 ms 26192 KB Output is correct
46 Correct 182 ms 45360 KB Output is correct
47 Correct 206 ms 45376 KB Output is correct
48 Correct 177 ms 45480 KB Output is correct
49 Correct 176 ms 45340 KB Output is correct
50 Correct 48 ms 26440 KB Output is correct
51 Correct 54 ms 26428 KB Output is correct
52 Correct 46 ms 26448 KB Output is correct
53 Correct 127 ms 45936 KB Output is correct
54 Correct 111 ms 45808 KB Output is correct
55 Correct 112 ms 45800 KB Output is correct
56 Correct 3 ms 9052 KB Output is correct
57 Correct 14 ms 13272 KB Output is correct
58 Correct 76 ms 31768 KB Output is correct
59 Correct 182 ms 52548 KB Output is correct
60 Correct 82 ms 44640 KB Output is correct
61 Correct 122 ms 43716 KB Output is correct