Submission #974799

#	Time	Username	Problem	Language	Result	Execution time	Memory
974799		KasymK	Cat in a tree (BOI17_catinatree)	C++17	11 / 100	1018 ms	3596 KiB

catinatree

#include "bits/stdc++.h"

using namespace std;

const int N = 1e5 + 5;

int n, d;
int mx = INT_MIN;

vector<int> adj[N], bit;

int vis[N], dis[N];

int in_yakyn(int id){
    for(int i = 0; i < n; ++i)
        vis[i] = dis[i] = 0;
    queue<int> q;
    q.push(id);
    vis[id] = 1;
    while(!q.empty()){
        int x = q.front();
        q.pop();
        for(auto i : adj[x])
            if(!vis[i]){
                vis[i] = 1;
                q.push(i);
                dis[i] = dis[x] + 1;
                if(bit[i])
                    return dis[i];
            }
    }
}

bool barla(){
    int cnt = count(bit.begin(), bit.end(), 1);
    if(cnt <= 1)
        return 1;
    for(int i = 0; i < n; ++i)
        if(bit[i] and in_yakyn(i) < d)
            return 0;
    return 1;
}

void f(int x){
    if(x == n){
        int cnt = count(bit.begin(), bit.end(), 1);
        if(barla())
            mx = max(mx, cnt);
        return;
    }
    for(int i = 0; i <= 1; ++i){
        bit[x] = i;
        f(x + 1);
    }
}

int main(){
    ios::sync_with_stdio(false); cin.tie(nullptr);
    cin >> n >> d;
    for(int i = 1; i <= n - 1; ++i){
        int x;
        cin >> x;
        adj[x].push_back(i);
        adj[i].push_back(x);
    }
    bit.resize(n);
    f(0);
    cout << mx << "\n";
    return 0;
}

Compilation message (stderr)

catinatree.cpp: In function 'int in_yakyn(int)':
catinatree.cpp:17:16: warning: control reaches end of non-void function [-Wreturn-type]
   17 |     queue<int> q;
      |                ^

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