Submission #1035840

#	Time	Username	Problem	Language	Result	Execution time	Memory
1035840		phoenix	Cat in a tree (BOI17_catinatree)	C++17	51 / 100	1073 ms	16184 KiB

catinatree

#include <bits/stdc++.h>

using namespace std;

const int N = 200200;

int n, D;

int p[N];
int d[N];
vector<int> g[N];

bool us[N];
int dst[N];
queue<int> q;

void del(int v) {
    vector<int> vis(n);
    q.push(v);
    vis[v] = true;
    dst[v] = 0;
    while (!q.empty()) {
        v = q.front();
        us[v] = true;
        q.pop();
        if (dst[v] == D - 1) continue;
        for (int to : g[v]) {
            if (!vis[to]) {
                vis[to] = true;
                dst[to] = dst[v] + 1;
                q.push(to);
            }
        }
    }
}

int main() {
    ios::sync_with_stdio(0);
    cin.tie(0);
    cin >> n >> D;
    for (int i = 1; i < n; i++) {
        cin >> p[i];
        g[p[i]].push_back(i);
        g[i].push_back(p[i]);
    }
    for (int i = 1; i < n; i++) {
        d[i] = d[p[i]] + 1;
    }
    vector<int> ord(n);
    iota(ord.begin(), ord.end(), 0);
    sort(ord.begin(), ord.end(), [&](int a, int b) { return d[a] > d[b]; });
    
    int res = 0;

    for (int c : ord) {
        if (us[c]) continue;
        res++;
        del(c);
    }
    cout << res;
}

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