Submission #1193396

#	Time	Username	Problem	Language	Result	Execution time	Memory
1193396		akuyga	Cat in a tree (BOI17_catinatree)	C++20	100 / 100	25 ms	9920 KiB

catinatree

#include "bits/stdc++.h"
using namespace std;
#define ii pair<int,int>
#define f first
#define s second
#define mp make_pair
#define ll long long

int main(){
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    //they said that connected node will be always less than the node
    //so we can give the less one to always be parent
    int N,K;
    cin>>N>>K;
    vector<int> A[N];
    for(int i=1;i<N;i++){
        int x;
        cin>>x;
        A[x].push_back(i);
    }
    //using reverse idea we pick up node greedily and let's say we can't pick all node
    int c=N;
    vector<int> dp(N,0);
    //dp store depth
    for(int i=N-1;i>=0;i--){
        for(auto n:A[i]){
            if(dp[i]+dp[n]+1<K){
                //in this case we can say we can't choose this pair together
                //so u gotta delete some and we will greedily delete parent(i)
                //that's the first time enter the case
                dp[i]=max(dp[i],dp[n]+1);
                //and when we store dp we store the leaf node which is farrest for sure
                //and we can consider to choose node
                c--;
            }
            else {
                //when enter this case let's say there are a pair 
                dp[i]=min(dp[i],dp[n]+1);
            }
        }
    }
    cout<<c;
    
    
    // mark as unsolved I can't even describe how this will work gotta work more on this
    
}

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