Submission #347202

#	Time	Username	Problem	Language	Result	Execution time	Memory
347202		AmShZ	Cat in a tree (BOI17_catinatree)	C++11	100 / 100	510 ms	54764 KiB

catinatree

// khodaya khodet komak kon
//# pragma GCC target ("avx2")
//# pragma GCC optimize("Ofast")
//# pragma GCC optimize("unroll-loops")
//# pragma GCC target("avx,avx2,sse,sse2,fma")
# pragma comment(linker, "/stack:200000000")
# pragma GCC optimize("Ofast")
# include <bits/stdc++.h>
 
/*
// ordered_set 
# include <ext/pb_ds/assoc_container.hpp>
# include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
# define ordered_set tree<int, null_type,less<int>, rb_tree_tag,tree_order_statistics_node_update> 
*/
 
using namespace std;
 
typedef long long                                        ll;
typedef long double                                      ld;
typedef pair <int, int>                                  pii;
typedef pair <pii, int>                                  ppi;
typedef pair <int, pii>                                  pip;
typedef pair <pii, pii>                                  ppp;
typedef pair <ll, ll>                                    pll;
 
# define A                                               first
# define B                                               second
# define endl                                            '\n'
# define sep                                             ' '
# define all(x)                                          x.begin(), x.end()
# define kill(x)                                         return cout << x << endl, 0
# define SZ(x)                                           int(x.size())
# define lc                                              id << 1
# define rc                                              id << 1 | 1
# define InTheNameOfGod                                  ios::sync_with_stdio(0);cin.tie(0); cout.tie(0);
 
ll power(ll a, ll b, ll md) {return (!b ? 1 : (b & 1 ? a * power(a * a % md, b / 2, md) % md : power(a * a % md, b / 2, md) % md));}
 
const int xn = 2e5 + 10;
const int xm = 10 + 10;
const int sq = 10;
const int inf = 1e9 + 10;
const ll INF = 1e18 + 10;
const int mod = 998244353;
const int base = 257;

int n, sz[xn], H[xn], ord[xn];
int f[xn], ans, d, ptr[xn];
pii rts[xn][xm];
vector <int> adj[xn];
bool hide[xn];

void plant(int v, int p = - 1){
	sz[v] = 1;
	for (int u : adj[v])
		if (u != p && !hide[u])
			plant(u, v), sz[v] += sz[u];
}
void add(int v, int root, int h = 0, int p = - 1){
	rts[v][ptr[v] ++] = {root, h};
	for (int u : adj[v])
		if (!hide[u] && u != p)
			add(u, root, h + 1, v);
}
int find_centroid(int v, int s, int p = - 1){
	for (int u : adj[v])
		if (!hide[u] && u != p && sz[u] + sz[u] > s)
			return find_centroid(u, s, v);
	return v;
}
void solve(int v){
	plant(v);
	v = find_centroid(v, sz[v]);
	f[v] = inf, add(v, v);
	hide[v] = true;
	for (int u : adj[v])
		if (!hide[u])
			solve(u);
}
bool cmp(int v, int u){ return H[v] > H[u];}

int main(){
	InTheNameOfGod;
	
	cin >> n >> d;
	for (int i = 1; i < n; ++ i){
		int par;
		cin >> par;
		adj[par].push_back(i);
		adj[i].push_back(par);
		H[i] = H[par] + 1;
		ord[i] = i;
	}
	solve(0);
	sort(ord, ord + n, cmp);
	for (int i = 0; i < n; ++ i){
		int v = ord[i];
		bool flag = false;
		for (int j = 0; j < ptr[v]; ++ j)
			flag |= rts[v][j].B + f[rts[v][j].A] < d;
		if (flag)
			continue;
		++ ans;
		for (int j = 0; j < ptr[v]; ++ j)
			f[rts[v][j].A] = min(f[rts[v][j].A], rts[v][j].B);
	}
	cout << ans << endl;
	
	return 0;
}

Compilation message (stderr)

catinatree.cpp:6: warning: ignoring #pragma comment  [-Wunknown-pragmas]
    6 | # pragma comment(linker, "/stack:200000000")
      |

• Subtask 1: 11 / 11
• Subtask 2: 40 / 40
• Subtask 3: 49 / 49