Submission #1115989

#	Time	Username	Problem	Language	Result	Execution time	Memory
1115989		vjudge1	Cat in a tree (BOI17_catinatree)	C++17	100 / 100	118 ms	35668 KiB

catinatree

#include <bits/stdc++.h>
using namespace std;
#define endl '\n'
#define int long long
int d;
const int MAXN=2*1e5;
vector<vector<int>> graph(MAXN);
vector<multiset<int>> choose(MAXN);
int depth[MAXN];
void DFS(int u){
    choose[u].insert(depth[u]);
    for(int v:graph[u]){
        depth[v]=depth[u]+1;
        DFS(v);
        if(choose[u].size()<choose[v].size()){
            swap(choose[u],choose[v]);
        }
        while(choose[v].size()>0){
            int x=*(choose[v].begin());
            choose[u].insert(x);
            choose[v].erase(choose[v].begin());
        }
    }
    while(choose[u].size()>1){
        multiset<int>::iterator it1=choose[u].begin();
        multiset<int>::iterator it2=it1;
        it2++;
        if((*it1)+(*it2)-2*depth[u]<d){
            choose[u].erase(choose[u].begin());
        }
        else{
            break;
        }
    }
}
signed main(){
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    int n;
    cin >> n >> d;
    for(int i=1;i<n;i++){
        int p;
        cin >> p;
        graph[p].push_back(i);
    }
    DFS(0);
    cout << choose[0].size() << endl;
}

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