Submission #736612

#	Time	Username	Problem	Language	Result	Execution time	Memory
736612		josanneo22	Cat in a tree (BOI17_catinatree)	C++17	100 / 100	29 ms	5360 KiB

catinatree

#include<bits/stdc++.h>
using namespace std;

#define pb push_back
#define pii pair<int,int>
const int inf=1000000010;
const int MAXN=200010, LOG=20;
int n, D, u, v, x, y, t, a, b, ans;
int par[MAXN];
pii dp[MAXN][2], dpt[2];
 
inline void Add(int v, int u){
	for (int i:{0, 1}) dpt[i]=dp[v][i];
	for (int i:{0, 1}) for (int j:{0, 1}) if (dpt[i].second+dp[u][j].second>=D){
		pii p={dpt[i].first+dp[u][j].first, min(dpt[i].second, dp[u][j].second)};
		if (p>dp[v][0]) swap(dp[v][0], p);
		if (p.first!=dp[v][0].first && p>dp[v][1]) swap(dp[v][1], p);
	}
}

void solve(){
	cin>>n>>D;
	for (int i=1; i<n; i++) cin>>par[i];
	for (int i=0; i<n; i++) dp[i][0]={1, 0}, dp[i][1]={0, inf};
	for (int i=n-1; i; i--){
		dp[i][0].second++;
		dp[i][1].second++;
		Add(par[i], i);
	}
	cout<<dp[0][0].first<<"\n";
}
int main(){
	ios_base::sync_with_stdio(0); cin.tie(0);
	solve();
}

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