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Submission #907729

# Submission time Handle Problem Language Result Execution time Memory
907729 2024-01-16T03:10:11 Z shoryu386 Cat in a tree (BOI17_catinatree) C++17
100 / 100
 996 ms 97240 KB 
#include <bits/stdc++.h>
using namespace std;

#define int long long

vector<int> adj[200007];

int depth[200007];
bitset<200007> marked;
void dfs(int x, int p, int d){
	depth[x] = d;
	
	for (auto y : adj[x]){
		if (y == p) continue;
		dfs(y, x, d+1);
	}
}

int dfsMarked(int x, int p){
	int ans = INT_MAX;
	if (marked[x]) return 0;
	
	for (auto y : adj[x]){
		if (y == p) continue;
		ans = min(dfsMarked(y, x) + 1, ans);
	}
	return ans;
}

int n, m; 
#define MAXN 200001
#define LOGN 20
vector<int> al[MAXN];
int dist[MAXN];
int ss[MAXN]; int lvl[MAXN];
int dfsSS(int x, int p, int l){
	ss[x] = 1;
	for (int i : al[x]){
		if (i == p || lvl[i] != -1) continue;
		
		ss[x] += dfsSS(i, x, l);
	}
	return ss[x];
}

vector<int> decomp[MAXN];

void dfsDist(int x, int p, int carry){
	dist[x] = carry;
	if (p != -1) decomp[x].push_back(p);
	for (int i : al[x]){
		if (i == p) continue;
		dfsDist(i, x, carry+1); 
	}
	return;
}

int centroidFind(int x, int p, int subtreesize){
	//cout << x << ' ' << p << ' ' << subtreesize << "\n\n\n";
	for (int i : al[x]){
		if (i == p || lvl[i] != -1) continue;
		if (ss[i] > subtreesize/2) return centroidFind(i, x, subtreesize);
	}
	return x;
}

int centPar[MAXN];
void centroidTreeCreate(int x, int p, int level){
	int stsize = dfsSS(x, p, level);
	int cent = centroidFind(x, -1, stsize);
	lvl[cent] = level;
	if (p == -1) p = cent;
	
	centPar[cent] = p;
	for (int i : al[cent]){
		if (lvl[i] == -1) centroidTreeCreate(i, cent, level+1);
	}	
}

//property: LCA between x and y on centroid tree will appear in path between x and y
//so traversing up the centroid tree from z tells us all possible paths if we treat each ancestor correctly

int kthPar(int a, int k){
	for (int x = 0; x < LOGN; x++){
		if (k & (1<<x)) a = decomp[a][x];
	}
	return a;
}

int lca(int a, int b){
	if (dist[a] > dist[b]) swap(a, b);
	
	if (dist[a] != dist[b]) b = kthPar(b, dist[b] - dist[a]);
	
	for (int x = LOGN; x > -1; x--){
		if ((int)decomp[a].size() > x && (int)decomp[b].size() > x && decomp[a][x] != decomp[b][x]){
			a = decomp[a][x]; b = decomp[b][x];
		}
	}
	if (a == b) return a;
	return decomp[a][0];
	
}

int closest[MAXN];

void update(int root, int x, int level){
	closest[x] = min(closest[x], dist[root]+dist[x]-2*dist[lca(root, x)]);
	while (level != 0){
		x = centPar[x]; level--;
		closest[x] = min(closest[x], dist[root]+dist[x]-2*dist[lca(root, x)]);
	}
}

bool red[MAXN];

int query(int root, int x, int level){
	
	int ans = closest[x];
	
	while (level != 0){
		x = centPar[x];
		ans = min(closest[x]+dist[root]+dist[x]-2*dist[lca(root, x)], ans);
		level--;
	}
	return ans;
}


main(){
	int d; cin >> n >> d;
	int p[n];
	for (int x = 1; x < n; x++){
		cin >> p[x];
		
		adj[x].push_back(p[x]);
		al[x].push_back(p[x]);
		adj[p[x]].push_back(x);
		al[p[x]].push_back(x);
	}
	
	dfs(0, -1, 0);
	
	vector<int> depthOrder[200007];
	for (int x = 0; x < n; x++){
		depthOrder[depth[x]].push_back(x);
	}
	
	memset(lvl, -1, sizeof(lvl)); for (int x = 0; x < n; x++) closest[x] = INT_MAX;
	memset(dist, -1, sizeof(dist));
	dfsDist(0, -1, 0);

	for (int x = 0; x < LOGN; x++){
		for (int y = 0; y < n; y++){
			if ((int)decomp[y].size() > x && (int)decomp[decomp[y][x]].size() > x) decomp[y].push_back(decomp[decomp[y][x]][x]);
		}
	}
	
	centroidTreeCreate(0, -1, 0);

	
	int ans = 0;
	for (int x = 200000; x > -1; x--){
		for (auto y : depthOrder[x]){
			//cout << y << ' ' << dfsMarked(y, -1) << '\n';
			
			if (query(y, y, lvl[y]) >= d){
				update(y, y, lvl[y]); red[y] = 1;
				
				marked[y] = 1;
				ans++;
			}
			
			//cout << y << ' ' << marked[y] << '\n';
		}
	}
	cout << ans;
}

Compilation message

catinatree.cpp:130:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
  130 | main(){
      | ^~~~

Subtask #1
11.0 / 11.0

# Verdict Execution time Memory Grader output
1 Correct 10 ms 28504 KB Output is correct
2 Correct 11 ms 28508 KB Output is correct
3 Correct 11 ms 28504 KB Output is correct
4 Correct 11 ms 28504 KB Output is correct
5 Correct 10 ms 28504 KB Output is correct
6 Correct 12 ms 28508 KB Output is correct
7 Correct 11 ms 28504 KB Output is correct
8 Correct 10 ms 28508 KB Output is correct
9 Correct 11 ms 28508 KB Output is correct
10 Correct 10 ms 28508 KB Output is correct
11 Correct 10 ms 28508 KB Output is correct
12 Correct 10 ms 28508 KB Output is correct
13 Correct 10 ms 28508 KB Output is correct
14 Correct 13 ms 28508 KB Output is correct
15 Correct 11 ms 28508 KB Output is correct
16 Correct 11 ms 28508 KB Output is correct
17 Correct 12 ms 28864 KB Output is correct
18 Correct 11 ms 28504 KB Output is correct
19 Correct 12 ms 28508 KB Output is correct
20 Correct 11 ms 28504 KB Output is correct

Subtask #2
40.0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 10 ms 28504 KB Output is correct
2 Correct 11 ms 28508 KB Output is correct
3 Correct 11 ms 28504 KB Output is correct
4 Correct 11 ms 28504 KB Output is correct
5 Correct 10 ms 28504 KB Output is correct
6 Correct 12 ms 28508 KB Output is correct
7 Correct 11 ms 28504 KB Output is correct
8 Correct 10 ms 28508 KB Output is correct
9 Correct 11 ms 28508 KB Output is correct
10 Correct 10 ms 28508 KB Output is correct
11 Correct 10 ms 28508 KB Output is correct
12 Correct 10 ms 28508 KB Output is correct
13 Correct 10 ms 28508 KB Output is correct
14 Correct 13 ms 28508 KB Output is correct
15 Correct 11 ms 28508 KB Output is correct
16 Correct 11 ms 28508 KB Output is correct
17 Correct 12 ms 28864 KB Output is correct
18 Correct 11 ms 28504 KB Output is correct
19 Correct 12 ms 28508 KB Output is correct
20 Correct 11 ms 28504 KB Output is correct
21 Correct 13 ms 29020 KB Output is correct
22 Correct 11 ms 28508 KB Output is correct
23 Correct 11 ms 28508 KB Output is correct
24 Correct 12 ms 28744 KB Output is correct
25 Correct 12 ms 29172 KB Output is correct
26 Correct 12 ms 28760 KB Output is correct
27 Correct 12 ms 28764 KB Output is correct
28 Correct 12 ms 28764 KB Output is correct
29 Correct 14 ms 28764 KB Output is correct
30 Correct 11 ms 28764 KB Output is correct
31 Correct 12 ms 28772 KB Output is correct
32 Correct 11 ms 28792 KB Output is correct
33 Correct 11 ms 28764 KB Output is correct
34 Correct 11 ms 28760 KB Output is correct
35 Correct 11 ms 28764 KB Output is correct
36 Correct 11 ms 28804 KB Output is correct
37 Correct 14 ms 29016 KB Output is correct
38 Correct 12 ms 28764 KB Output is correct
39 Correct 13 ms 29020 KB Output is correct
40 Correct 13 ms 29016 KB Output is correct

Subtask #3
49.0 / 49.0

# Verdict Execution time Memory Grader output
1 Correct 10 ms 28504 KB Output is correct
2 Correct 11 ms 28508 KB Output is correct
3 Correct 11 ms 28504 KB Output is correct
4 Correct 11 ms 28504 KB Output is correct
5 Correct 10 ms 28504 KB Output is correct
6 Correct 12 ms 28508 KB Output is correct
7 Correct 11 ms 28504 KB Output is correct
8 Correct 10 ms 28508 KB Output is correct
9 Correct 11 ms 28508 KB Output is correct
10 Correct 10 ms 28508 KB Output is correct
11 Correct 10 ms 28508 KB Output is correct
12 Correct 10 ms 28508 KB Output is correct
13 Correct 10 ms 28508 KB Output is correct
14 Correct 13 ms 28508 KB Output is correct
15 Correct 11 ms 28508 KB Output is correct
16 Correct 11 ms 28508 KB Output is correct
17 Correct 12 ms 28864 KB Output is correct
18 Correct 11 ms 28504 KB Output is correct
19 Correct 12 ms 28508 KB Output is correct
20 Correct 11 ms 28504 KB Output is correct
21 Correct 13 ms 29020 KB Output is correct
22 Correct 11 ms 28508 KB Output is correct
23 Correct 11 ms 28508 KB Output is correct
24 Correct 12 ms 28744 KB Output is correct
25 Correct 12 ms 29172 KB Output is correct
26 Correct 12 ms 28760 KB Output is correct
27 Correct 12 ms 28764 KB Output is correct
28 Correct 12 ms 28764 KB Output is correct
29 Correct 14 ms 28764 KB Output is correct
30 Correct 11 ms 28764 KB Output is correct
31 Correct 12 ms 28772 KB Output is correct
32 Correct 11 ms 28792 KB Output is correct
33 Correct 11 ms 28764 KB Output is correct
34 Correct 11 ms 28760 KB Output is correct
35 Correct 11 ms 28764 KB Output is correct
36 Correct 11 ms 28804 KB Output is correct
37 Correct 14 ms 29016 KB Output is correct
38 Correct 12 ms 28764 KB Output is correct
39 Correct 13 ms 29020 KB Output is correct
40 Correct 13 ms 29016 KB Output is correct
41 Correct 204 ms 51764 KB Output is correct
42 Correct 262 ms 44744 KB Output is correct
43 Correct 190 ms 44368 KB Output is correct
44 Correct 189 ms 44368 KB Output is correct
45 Correct 234 ms 44676 KB Output is correct
46 Correct 593 ms 60344 KB Output is correct
47 Correct 509 ms 61252 KB Output is correct
48 Correct 590 ms 61384 KB Output is correct
49 Correct 612 ms 61120 KB Output is correct
50 Correct 131 ms 43848 KB Output is correct
51 Correct 138 ms 44116 KB Output is correct
52 Correct 130 ms 43940 KB Output is correct
53 Correct 388 ms 59168 KB Output is correct
54 Correct 328 ms 58952 KB Output is correct
55 Correct 341 ms 59200 KB Output is correct
56 Correct 15 ms 29272 KB Output is correct
57 Correct 62 ms 35180 KB Output is correct
58 Correct 372 ms 63068 KB Output is correct
59 Correct 996 ms 97240 KB Output is correct
60 Correct 194 ms 55192 KB Output is correct
61 Correct 380 ms 61400 KB Output is correct