Submission #562732

#	Time	Username	Problem	Language	Result	Execution time	Memory
562732		anubhavdhar	Cat in a tree (BOI17_catinatree)	C++14	100 / 100	140 ms	15540 KiB

catinatree

#include<bits/stdc++.h>

#define ll long long
#define pb push_back
#define mp make_pair
#define pii pair<int, int>
#define pll pair<ll, ll>
#define ff first 
#define ss second
#define vi vector<int>
#define vl vector<ll>
#define vii vector<pii>
#define vll vector<pll>
#define FOR(i,N) for(i=0;i<(N);++i)
#define FORe(i,N) for(i=1;i<=(N);++i)
#define FORr(i,a,b) for(i=(a);i<(b);++i)
#define FORrev(i,N) for(i=(N);i>=0;--i)
#define F0R(i,N) for(int i=0;i<(N);++i)
#define F0Re(i,N) for(int i=1;i<=(N);++i)
#define F0Rr(i,a,b) for(ll i=(a);i<(b);++i)
#define F0Rrev(i,N) for(int i=(N);i>=0;--i)
#define all(v) (v).begin(),(v).end()
#define dbgLine cerr<<" LINE : "<<__LINE__<<"\n"
#define ldd long double
 
using namespace std;
 
const int Alp = 26;
const int __PRECISION = 9;
const int inf = 1e9 + 8;
 
const ldd PI = acos(-1);
const ldd EPS = 1e-7;

const ll MOD = 1e9 + 7;
const ll MAXN = 2e5 + 5;
const ll ROOTN = 640;
const ll LOGN = 18;
const ll INF = 1e18 + 1022;

int N, D;
vector<int> dep(MAXN), dis(MAXN), g[MAXN];

void dfs(int a, int p = -1, int d = D){
	if(dis[a] >= d){
		return;
	}
	dis[a] = d;
	for(int b : g[a]){
		if(p != b){
			dfs(b, a, d - 1);
		}
	}
}

signed main()
{

	
	ios_base::sync_with_stdio(false);
	cin.tie(NULL);
	cout.tie(NULL);
	

	cin>>N>>D;


	F0Re(i, N-1)
	{
		int j;
		cin>>j;
		g[i + 1].pb(j + 1);
		g[j + 1].pb(i + 1);
		dep[i + 1] = dep[j + 1] + 1;
	}

	if(D >= N)
	{
		cout<<"1\n";
		exit(0);
	}
	if(D == 1)
	{
		cout<<N<<'\n';
		exit(0);
	}
	// dbgLine;
	vi V(N);
	iota(all(V), 1);
	sort(all(V), [&](int a, int b){return dep[a] > dep[b];});
	int ans = 0;
	for(int u : V){
		if(dis[u]){
			continue;
		}
		++ans;
		dfs(u);
	}

	cout << ans << '\n';
 
	return 0;
}

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