Submission #447475

#	Time	Username	Problem	Language	Result	Execution time	Memory
447475		kym	Cat in a tree (BOI17_catinatree)	C++14	0 / 100	4 ms	4940 KiB

catinatree

#include <bits/stdc++.h>
using namespace std;
#define int ll 
#define FOR(i,s,e) for(ll i = s; i <= (ll)e; ++i)
#define DEC(i,s,e) for(ll i = s; i >= (ll)e; --i)
#define IAMSPEED ios_base::sync_with_stdio(false); cin.tie(0);
#ifdef LOCAL
#define db(x) cerr << #x << "=" << x << "\n"
#define db2(x, y) cerr << #x << "=" << x << " , " << #y << "=" << y << "\n"
#define db3(a,b,c) cerr<<#a<<"="<<a<<","<<#b<<"="<<b<<","<<#c<<"="<<c<<"\n"
#define dbv(v) cerr << #v << ":"; for (auto ite : v) cerr << ite << ' '; cerr <<"\n"
#define dbvp(v) cerr << #v << ":"; for (auto ite : v) cerr << "{"  << ite.f << ',' << ite.s << "} "; cerr << "\n"
#define dba(a,ss,ee) cerr << #a << ":"; FOR(ite,ss,ee) cerr << a[ite] << ' '; cerr << "\n"
#define reach cerr << "LINE: " << __LINE__ << "\n";
#else
#define db(x)
#define db2(x,y)
#define db3(a,b,c)
#define dbv(v)
#define dbvp(v)
#define dba(a,ss,ee)
#define reach 
#endif
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
#define ll long long 
#define pb push_back
#define eb emplace_back
#define all(x) (x).begin(), (x).end()
#define f first
#define s second
#define g0(x) get<0>(x)
#define g1(x) get<1>(x)
#define g2(x) get<2>(x)
#define g3(x) get<3>(x)
typedef pair <ll, ll> pi;
typedef tuple<ll,ll,ll> ti3;
typedef tuple<ll,ll,ll,ll> ti4;
ll rand(ll a, ll b) { return a + rng() % (b-a+1); }
const int MOD = 1e9 + 7;
const int inf = (int)1e9 + 500;
const long long oo = (ll)1e18 + 500;
template <typename T> void chmax(T& a, const T b) { a=max(a,b); }
template <typename T> void chmin(T& a, const T b) { a=min(a,b); }
const int MAXN = 200005;
int n, d;
vector<int> V[MAXN];
int depth[MAXN],mxdepth[MAXN];
int ans;
void dfs1(int x, int lvl) {
	depth[x] = mxdepth[x] = lvl;
	for(auto v:V[x]) {
		dfs1(v,lvl+1);
		chmax(mxdepth[x],mxdepth[v]);
	}
}

pi dfs2(int x, int di) {
	db2(x,di);
	sort(all(V[x]),[](int a, int b) {
		return mxdepth[a] > mxdepth[b];
	});
	if(V[x].size()==0) {
		if(di==-1||di>d){
			++ans;
			return pi(0,1);
		} else {
			return pi(--di,-1);
		}
	}
	bool f=0;
	for(auto v:V[x]) {
		pi r;
		if(di==-1) {
			r=dfs2(v,di);
		} else {
			r=dfs2(v,di+1);
		}
		db2(r.f,r.s);
		if(r.s==-1) { //not found
			break;
		}
		else{
			f=1;	
			di=r.f+1;
			
		}
	}
	if(f) {
		
		if(di==d) {
			++ans;
			return pi(0,1);
		} else {
			return pi(++di,1);
		}
	} else {
		return pi(--di,-1);
	}
}

int32_t main() 
{
	IAMSPEED
	cin >> n >> d;
	FOR(i,1,n-1) {
		int x; cin >> x;
		V[x].pb(i);
	}
	dfs1(0, 0);
	dfs2(0,-1);
	cout << ans;
}

• Subtask 1: 0 / 11
• Subtask 2: 0 / 40
• Subtask 3: 0 / 49