Submission #530007

#	Time	Username	Problem	Language	Result	Execution time	Memory
530007		Alex_tz307	Cat in a tree (BOI17_catinatree)	C++17	100 / 100	155 ms	16248 KiB

catinatree

#include <bits/stdc++.h>

using namespace std;

const int kN = 2e5;
vector<int> g[kN];
int dep[kN], mark[kN];
bitset<kN> done;

void dfs(int u, int d) {
  mark[u] = d;
  d -= 1;
  if (d) {
    for (int v : g[u]) {
      if (!done[dep[v]] && mark[v] < d) {
        dfs(v, d);
      }
    }
  }
}

void testCase() {
  int n, d;
  cin >> n >> d;
  vector<pair<int, int>> nodes(n, {0, 0});
  for (int v = 1; v < n; ++v) {
    int u;
    cin >> u;
    g[u].emplace_back(v);
    g[v].emplace_back(u);
    dep[v] = dep[u] + 1;
    nodes[v] = {dep[v], v};
  }
  sort(nodes.begin(), nodes.end(), greater<pair<int, int>>());
  int ans = 0, last = -1;
  for (auto it : nodes) {
    if (last != -1 && last < it.first) {
      done[last] = true;
    }
    if (mark[it.second] == 0) {
      ans += 1;
      dfs(it.second, d);
    }
    last = it.first;
  }
  cout << ans << '\n';
}

int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(nullptr);
  int tests = 1;
  for (int tc = 0; tc < tests; ++tc) {
    testCase();
  }
  return 0;
}

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