oj.uz

Submission #415298

# Submission time Handle Problem Language Result Execution time Memory
415298 2021-05-31T20:41:07 Z Blagojce Cat in a tree (BOI17_catinatree) C++11
100 / 100
 582 ms 54152 KB 
#include <bits/stdc++.h>
#define fr(i, n, m) for(int i = (n); i < (m); i ++)
#define pb push_back
#define st first
#define nd second
#define pq priority_queue
#define all(x) begin(x), end(x)
  
using namespace std;
typedef long long ll;
typedef long double ld;
typedef pair<ll,ll> pii;
const ll inf = 1e18;
const int i_inf = 1e9;
const ll mod = 1e9+7;

mt19937 _rand(time(NULL));
const int mxn = 2e5;

int n, d;

vector<int> g[mxn];

int sub[mxn];
bool deleted[mxn];

int cn;

int dep[mxn];
int sparse[mxn][19];

void dfs(int u, int p){
	sparse[u][0] = p;
	fr(i, 1, 19) sparse[u][i] = sparse[sparse[u][i-1]][i-1];
	for(auto e : g[u]){
		if(e == p) continue;
		dep[e] = dep[u] + 1;
		dfs(e, u);
	}
}

void dfs0(int u, int p){
	sub[u] = 1;
	for(auto e : g[u]){
		if(e == p || deleted[e]) continue;
		dfs0(e, u);
		sub[u] += sub[e];
	}
}

int dfs1(int u, int p){
	for(auto e : g[u]){
		if(e == p || deleted[e]) continue;
		if(sub[e] > cn /2) return dfs1(e, u);
	}
	return u;
}
int current_dep;

int pre[mxn][19];



void dfs2(int u, int p){
	for(auto e : g[u]){
		if(e == p || deleted[e]) continue;
		pre[e][current_dep] = pre[u][current_dep] + 1;
		dfs2(e, u);
	}
}


int link[mxn];

int cdep[mxn];

void decompose(int u, int p, int d){
	dfs0(u, u);
	cn = sub[u];
	int cen = dfs1(u, u);
	link[cen] = p;
	
	current_dep = d;
	cdep[cen] = d;
	pre[cen][d] = 0;
	dfs2(cen, cen);
	
	deleted[cen] = true;
	for(auto e : g[cen]){
		if(!deleted[e]){
			decompose(e, cen, d + 1);
		}
	}
}

int lca(int a, int b){
	int d = min(dep[a], dep[b]);
	for(int i = 18; i >= 0; i --){
		if(dep[a] - (1<<i) >= d){
			a = sparse[a][i];
		}
		if(dep[b] - (1<<i) >= d){
			b = sparse[b][i];
		}
	}
	if(a == b) return a;
	
	for(int i = 18; i >= 0; i--){
		if(sparse[a][i] != sparse[b][i]){
			a = sparse[a][i];
			b = sparse[b][i];
		}
	}
	return sparse[a][0];
}

int minw[mxn];


bool check(int u){
	int x = u;
	while(x != -1){
		//optimization : 
		int w = minw[x] + pre[u][cdep[x]];
		
		//slow version : 
		//int w = minw[x] + dep[x] + dep[u] - 2*dep[lca(x, u)];
		
		if(w < d) return false;
		
		x = link[x];
	}
	return true;
}
void update(int u){
	int x = u;
	while(x != -1){
		//optimization : 
		int w = pre[u][cdep[x]];
		
		
		//slow version : 
		//int w = dep[x] + dep[u] - 2*dep[lca(x, u)];
		
		minw[x] = min(minw[x], w);
		x = link[x];
	}
}

void solve(){
	cin >> n >> d;
	fr(i, 1, n){
		int x;
		cin >> x;
		g[i].pb(x);
		g[x].pb(i);
	}
	dfs(0, 0);
	decompose(0, -1, 0);
	vector<int> v;
	fr(i, 0, n) v.pb(i);
	sort(all(v), [](const int &i, const int &j){
		return dep[i] > dep[j];
	});
	fr(i, 0, n){
		minw[i] = 1e9;
	}
	int ans = 0;
	for(auto u : v){
		if(check(u)){
			update(u);
			++ans;
		}
	}
	cout<<ans<<endl;
}

int main(){
	ios_base::sync_with_stdio(false);
	cin.tie(NULL);
	cout.tie(NULL);
	solve();
}

Subtask #1
11.0 / 11.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 4992 KB Output is correct
2 Correct 5 ms 4940 KB Output is correct
3 Correct 4 ms 5068 KB Output is correct
4 Correct 4 ms 5024 KB Output is correct
5 Correct 4 ms 4940 KB Output is correct
6 Correct 5 ms 5068 KB Output is correct
7 Correct 5 ms 5068 KB Output is correct
8 Correct 5 ms 5024 KB Output is correct
9 Correct 5 ms 5068 KB Output is correct
10 Correct 5 ms 5068 KB Output is correct
11 Correct 4 ms 5068 KB Output is correct
12 Correct 4 ms 5020 KB Output is correct
13 Correct 4 ms 5068 KB Output is correct
14 Correct 4 ms 5016 KB Output is correct
15 Correct 4 ms 5068 KB Output is correct
16 Correct 4 ms 5068 KB Output is correct
17 Correct 4 ms 5068 KB Output is correct
18 Correct 4 ms 5068 KB Output is correct
19 Correct 4 ms 5020 KB Output is correct
20 Correct 5 ms 5068 KB Output is correct

Subtask #2
40.0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 4992 KB Output is correct
2 Correct 5 ms 4940 KB Output is correct
3 Correct 4 ms 5068 KB Output is correct
4 Correct 4 ms 5024 KB Output is correct
5 Correct 4 ms 4940 KB Output is correct
6 Correct 5 ms 5068 KB Output is correct
7 Correct 5 ms 5068 KB Output is correct
8 Correct 5 ms 5024 KB Output is correct
9 Correct 5 ms 5068 KB Output is correct
10 Correct 5 ms 5068 KB Output is correct
11 Correct 4 ms 5068 KB Output is correct
12 Correct 4 ms 5020 KB Output is correct
13 Correct 4 ms 5068 KB Output is correct
14 Correct 4 ms 5016 KB Output is correct
15 Correct 4 ms 5068 KB Output is correct
16 Correct 4 ms 5068 KB Output is correct
17 Correct 4 ms 5068 KB Output is correct
18 Correct 4 ms 5068 KB Output is correct
19 Correct 4 ms 5020 KB Output is correct
20 Correct 5 ms 5068 KB Output is correct
21 Correct 6 ms 5452 KB Output is correct
22 Correct 5 ms 5068 KB Output is correct
23 Correct 5 ms 5068 KB Output is correct
24 Correct 4 ms 5068 KB Output is correct
25 Correct 6 ms 5196 KB Output is correct
26 Correct 5 ms 5280 KB Output is correct
27 Correct 5 ms 5276 KB Output is correct
28 Correct 6 ms 5324 KB Output is correct
29 Correct 5 ms 5324 KB Output is correct
30 Correct 5 ms 5324 KB Output is correct
31 Correct 5 ms 5280 KB Output is correct
32 Correct 5 ms 5284 KB Output is correct
33 Correct 5 ms 5324 KB Output is correct
34 Correct 5 ms 5288 KB Output is correct
35 Correct 5 ms 5272 KB Output is correct
36 Correct 6 ms 5292 KB Output is correct
37 Correct 5 ms 5412 KB Output is correct
38 Correct 6 ms 5408 KB Output is correct
39 Correct 6 ms 5412 KB Output is correct
40 Correct 6 ms 5452 KB Output is correct

Subtask #3
49.0 / 49.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 4992 KB Output is correct
2 Correct 5 ms 4940 KB Output is correct
3 Correct 4 ms 5068 KB Output is correct
4 Correct 4 ms 5024 KB Output is correct
5 Correct 4 ms 4940 KB Output is correct
6 Correct 5 ms 5068 KB Output is correct
7 Correct 5 ms 5068 KB Output is correct
8 Correct 5 ms 5024 KB Output is correct
9 Correct 5 ms 5068 KB Output is correct
10 Correct 5 ms 5068 KB Output is correct
11 Correct 4 ms 5068 KB Output is correct
12 Correct 4 ms 5020 KB Output is correct
13 Correct 4 ms 5068 KB Output is correct
14 Correct 4 ms 5016 KB Output is correct
15 Correct 4 ms 5068 KB Output is correct
16 Correct 4 ms 5068 KB Output is correct
17 Correct 4 ms 5068 KB Output is correct
18 Correct 4 ms 5068 KB Output is correct
19 Correct 4 ms 5020 KB Output is correct
20 Correct 5 ms 5068 KB Output is correct
21 Correct 6 ms 5452 KB Output is correct
22 Correct 5 ms 5068 KB Output is correct
23 Correct 5 ms 5068 KB Output is correct
24 Correct 4 ms 5068 KB Output is correct
25 Correct 6 ms 5196 KB Output is correct
26 Correct 5 ms 5280 KB Output is correct
27 Correct 5 ms 5276 KB Output is correct
28 Correct 6 ms 5324 KB Output is correct
29 Correct 5 ms 5324 KB Output is correct
30 Correct 5 ms 5324 KB Output is correct
31 Correct 5 ms 5280 KB Output is correct
32 Correct 5 ms 5284 KB Output is correct
33 Correct 5 ms 5324 KB Output is correct
34 Correct 5 ms 5288 KB Output is correct
35 Correct 5 ms 5272 KB Output is correct
36 Correct 6 ms 5292 KB Output is correct
37 Correct 5 ms 5412 KB Output is correct
38 Correct 6 ms 5408 KB Output is correct
39 Correct 6 ms 5412 KB Output is correct
40 Correct 6 ms 5452 KB Output is correct
41 Correct 151 ms 44532 KB Output is correct
42 Correct 222 ms 25984 KB Output is correct
43 Correct 176 ms 25892 KB Output is correct
44 Correct 163 ms 25828 KB Output is correct
45 Correct 210 ms 25916 KB Output is correct
46 Correct 529 ms 46472 KB Output is correct
47 Correct 582 ms 46380 KB Output is correct
48 Correct 502 ms 46528 KB Output is correct
49 Correct 431 ms 46400 KB Output is correct
50 Correct 107 ms 26268 KB Output is correct
51 Correct 114 ms 26304 KB Output is correct
52 Correct 157 ms 26320 KB Output is correct
53 Correct 277 ms 47184 KB Output is correct
54 Correct 301 ms 47416 KB Output is correct
55 Correct 355 ms 47264 KB Output is correct
56 Correct 6 ms 5544 KB Output is correct
57 Correct 28 ms 11072 KB Output is correct
58 Correct 120 ms 32828 KB Output is correct
59 Correct 423 ms 54152 KB Output is correct
60 Correct 162 ms 45496 KB Output is correct
61 Correct 213 ms 44256 KB Output is correct