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Submission #927919

# Submission time Handle Problem Language Result Execution time Memory
927919 2024-02-15T14:05:19 Z TAhmed33 Cat in a tree (BOI17_catinatree) C++
100 / 100
 361 ms 40448 KB 
#include <bits/stdc++.h>
using namespace std;
const int MAXN = 2e5 + 25;
vector <int> adj[MAXN];
int p[MAXN], sze[MAXN]; 
int depth[MAXN];
bool vis[MAXN];
void calc (int pos, int par) {
	sze[pos] = 1;
	for (auto j : adj[pos]) {
		if (!vis[j] && j != par) {
			calc(j, pos);
			sze[pos] += sze[j];
		}
	}
}
int find (int pos, int par, int u) {
	for (auto j : adj[pos]) {
		if (j == par || vis[j]) continue;
		if (sze[j] > u / 2) return find(j, pos, u);
	}
	return pos;
}
void dfs (int pos, int par) {
	calc(pos, -1);
	int x = find(pos, -1, sze[pos]);
	vis[x] = 1;
	p[x] = par;
	for (auto j : adj[x]) {
		if (!vis[j]) {
			dfs(j, x);
		}
	}
}
int n, d;
 
struct LCA {
	int p2[MAXN] = {}, dep[MAXN] = {}, dp[MAXN][18] = {};
	void dfs (int pos, int par) {
		p2[pos] = par;
		for (auto j : adj[pos]) {
			if (j == par) continue;
			dep[j] = 1 + dep[pos];
			dfs(j, pos);
		}
	}
	int jump (int a, int b) {
		for (int i = 17; i >= 0; i--) {
			if ((b & (1 << i)) && dp[a][i]) a = dp[a][i];
			else if (b & (1 << i)) return -1;
		}
		return a;
	}
	int lca (int a, int b) {
		if (dep[a] < dep[b]) swap(a, b);
		int u = dep[a] - dep[b];
		a = jump(a, u);
		if (a == b) return a;
		for (int i = 17; i >= 0; i--) {
			int x = dp[a][i], y = dp[b][i];
			if (x && y && x != y) a = x, b = y;
		}
		return jump(a, 1);	
	}
	int dist (int a, int b) { return dep[a] + dep[b] - 2 * dep[lca(a, b)]; }
	void init () {
		dfs(1, 0);
		for (int i = 1; i <= n; i++) dp[i][0] = p2[i];
		for (int i = 1; i <= 17; i++) for (int j = 1; j <= n; j++) dp[j][i] = dp[dp[j][i - 1]][i - 1];
	}
};	
LCA cur;
int pp[MAXN];
bool check (int x) {
	int mn = 1e9;
	int u = x;
	while (u != -1) {
		mn = min(mn, cur.dist(x, u) + pp[u]);
		u = p[u];
	}
	return (mn >= d);
}
void mark (int x) {
	int u = x;
	while (u != -1) {
		pp[u] = min(pp[u], cur.dist(u, x));
		u = p[u];
	}
}
int main () {
	ios::sync_with_stdio(0);
	cin.tie(0);
	cin >> n >> d;
	for (int i = 2; i <= n; i++) {
		int x; cin >> x; x++;
		adj[i].push_back(x);
		adj[x].push_back(i);
	}
	cur.init();
	dfs(1, -1);
	vector <int> dd;
	for (int i = 1; i <= n; i++) pp[i] = 1e9;
	for (int i = 1; i <= n; i++) dd.push_back(i);
	sort(dd.begin(), dd.end(), [&] (int &a, int &b) {
		return cur.dep[a] > cur.dep[b];
	});
	int ans = 0;
	vector <int> ll;
	for (auto i : dd) if (check(i)) {
		ans++; mark(i); 
	}
	cout << ans << '\n';	
}

Subtask #1
11.0 / 11.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 13660 KB Output is correct
2 Correct 4 ms 13660 KB Output is correct
3 Correct 2 ms 13660 KB Output is correct
4 Correct 3 ms 13496 KB Output is correct
5 Correct 2 ms 13660 KB Output is correct
6 Correct 3 ms 13660 KB Output is correct
7 Correct 3 ms 13660 KB Output is correct
8 Correct 2 ms 13660 KB Output is correct
9 Correct 2 ms 13912 KB Output is correct
10 Correct 3 ms 13656 KB Output is correct
11 Correct 3 ms 13660 KB Output is correct
12 Correct 3 ms 13660 KB Output is correct
13 Correct 2 ms 13660 KB Output is correct
14 Correct 2 ms 13660 KB Output is correct
15 Correct 2 ms 13660 KB Output is correct
16 Correct 3 ms 13660 KB Output is correct
17 Correct 3 ms 13496 KB Output is correct
18 Correct 3 ms 13656 KB Output is correct
19 Correct 2 ms 13660 KB Output is correct
20 Correct 2 ms 13660 KB Output is correct

Subtask #2
40.0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 13660 KB Output is correct
2 Correct 4 ms 13660 KB Output is correct
3 Correct 2 ms 13660 KB Output is correct
4 Correct 3 ms 13496 KB Output is correct
5 Correct 2 ms 13660 KB Output is correct
6 Correct 3 ms 13660 KB Output is correct
7 Correct 3 ms 13660 KB Output is correct
8 Correct 2 ms 13660 KB Output is correct
9 Correct 2 ms 13912 KB Output is correct
10 Correct 3 ms 13656 KB Output is correct
11 Correct 3 ms 13660 KB Output is correct
12 Correct 3 ms 13660 KB Output is correct
13 Correct 2 ms 13660 KB Output is correct
14 Correct 2 ms 13660 KB Output is correct
15 Correct 2 ms 13660 KB Output is correct
16 Correct 3 ms 13660 KB Output is correct
17 Correct 3 ms 13496 KB Output is correct
18 Correct 3 ms 13656 KB Output is correct
19 Correct 2 ms 13660 KB Output is correct
20 Correct 2 ms 13660 KB Output is correct
21 Correct 4 ms 13660 KB Output is correct
22 Correct 3 ms 13660 KB Output is correct
23 Correct 4 ms 13660 KB Output is correct
24 Correct 3 ms 13660 KB Output is correct
25 Correct 4 ms 13660 KB Output is correct
26 Correct 3 ms 13736 KB Output is correct
27 Correct 3 ms 13660 KB Output is correct
28 Correct 4 ms 13660 KB Output is correct
29 Correct 3 ms 13656 KB Output is correct
30 Correct 3 ms 13760 KB Output is correct
31 Correct 3 ms 13660 KB Output is correct
32 Correct 3 ms 13660 KB Output is correct
33 Correct 3 ms 13660 KB Output is correct
34 Correct 3 ms 13660 KB Output is correct
35 Correct 3 ms 13772 KB Output is correct
36 Correct 3 ms 13660 KB Output is correct
37 Correct 4 ms 13796 KB Output is correct
38 Correct 3 ms 13660 KB Output is correct
39 Correct 4 ms 13816 KB Output is correct
40 Correct 4 ms 13696 KB Output is correct

Subtask #3
49.0 / 49.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 13660 KB Output is correct
2 Correct 4 ms 13660 KB Output is correct
3 Correct 2 ms 13660 KB Output is correct
4 Correct 3 ms 13496 KB Output is correct
5 Correct 2 ms 13660 KB Output is correct
6 Correct 3 ms 13660 KB Output is correct
7 Correct 3 ms 13660 KB Output is correct
8 Correct 2 ms 13660 KB Output is correct
9 Correct 2 ms 13912 KB Output is correct
10 Correct 3 ms 13656 KB Output is correct
11 Correct 3 ms 13660 KB Output is correct
12 Correct 3 ms 13660 KB Output is correct
13 Correct 2 ms 13660 KB Output is correct
14 Correct 2 ms 13660 KB Output is correct
15 Correct 2 ms 13660 KB Output is correct
16 Correct 3 ms 13660 KB Output is correct
17 Correct 3 ms 13496 KB Output is correct
18 Correct 3 ms 13656 KB Output is correct
19 Correct 2 ms 13660 KB Output is correct
20 Correct 2 ms 13660 KB Output is correct
21 Correct 4 ms 13660 KB Output is correct
22 Correct 3 ms 13660 KB Output is correct
23 Correct 4 ms 13660 KB Output is correct
24 Correct 3 ms 13660 KB Output is correct
25 Correct 4 ms 13660 KB Output is correct
26 Correct 3 ms 13736 KB Output is correct
27 Correct 3 ms 13660 KB Output is correct
28 Correct 4 ms 13660 KB Output is correct
29 Correct 3 ms 13656 KB Output is correct
30 Correct 3 ms 13760 KB Output is correct
31 Correct 3 ms 13660 KB Output is correct
32 Correct 3 ms 13660 KB Output is correct
33 Correct 3 ms 13660 KB Output is correct
34 Correct 3 ms 13660 KB Output is correct
35 Correct 3 ms 13772 KB Output is correct
36 Correct 3 ms 13660 KB Output is correct
37 Correct 4 ms 13796 KB Output is correct
38 Correct 3 ms 13660 KB Output is correct
39 Correct 4 ms 13816 KB Output is correct
40 Correct 4 ms 13696 KB Output is correct
41 Correct 78 ms 32352 KB Output is correct
42 Correct 135 ms 24268 KB Output is correct
43 Correct 79 ms 24272 KB Output is correct
44 Correct 78 ms 24264 KB Output is correct
45 Correct 80 ms 24264 KB Output is correct
46 Correct 227 ms 32720 KB Output is correct
47 Correct 186 ms 32708 KB Output is correct
48 Correct 221 ms 32728 KB Output is correct
49 Correct 204 ms 32704 KB Output is correct
50 Correct 51 ms 24532 KB Output is correct
51 Correct 53 ms 24532 KB Output is correct
52 Correct 51 ms 24528 KB Output is correct
53 Correct 129 ms 33228 KB Output is correct
54 Correct 166 ms 33168 KB Output is correct
55 Correct 123 ms 33228 KB Output is correct
56 Correct 5 ms 13656 KB Output is correct
57 Correct 24 ms 16116 KB Output is correct
58 Correct 131 ms 31184 KB Output is correct
59 Correct 361 ms 40448 KB Output is correct
60 Correct 96 ms 32544 KB Output is correct
61 Correct 138 ms 32212 KB Output is correct