oj.uz

Submission #559250

# Submission time Handle Problem Language Result Execution time Memory
559250 2022-05-09T14:40:20 Z Sweezy Cat in a tree (BOI17_catinatree) C++17
51 / 100
 1000 ms 30784 KB 
#include <bits/stdc++.h>
 
using namespace std;
// #define int long long

#ifdef LOCAL
#include "algo/debug.h"
#else
#define debug(...) 42
#endif

#define all(a) (a).begin(), (a).end()
#define rep(i, n) for (int i = 0; i < (n); ++i)
#define reps(i, s, n) for (int i = s; i < (n); ++i)
#define pb push_back
#define sz(a) (int) (a.size())

void solve() {
  int n, d;
  cin >> n >> d;
 
  if (d > n - 1) {
    cout << 1;
    return;
  }
 
  if (d == 0) {
    cout << n;
    return;
  }
 
  vector<vector<int>> g(n);
  reps(i, 1, n) {
    int p;
    cin >> p;
    g[p].push_back(i);
    g[i].push_back(p);
  }

  vector<int> s(n), used(n);
  function<void(int, int)> sizes = [&] (int v, int p) {
    s[v] = 1;
    for (auto &u : g[v]) {
      if (u != p && !used[u]) {
        sizes(u, v);
        s[v] += s[u];
      }
    }
  };

  function<int(int, int, int)> centroid = [&] (int v, int p, int n) {
    for (auto &u : g[v]) {
      if (u != p && !used[u] && s[u] > n / 2) {
        return centroid(u, v, n);
      } 
    }
    return v;
  };

  vector<vector<pair<int, int>>> centroids(n);
  function<void(int, int, int, int)> add_centroid = [&] (int v, int p, int centroid, int dist) {
    centroids[v].emplace_back(centroid, dist);
    for (auto &u : g[v]) {
      if (u != p && !used[u]) {
        add_centroid(u, v, centroid, dist + 1);
      }
    }
  };

  function<void(int)> decomposition1 = [&] (int v) {
    used[v] = 1;
    sizes(v, -1);

    add_centroid(v, -1, v, 0);

    for (auto &u : g[v]) {
      if (!used[u]) {
        decomposition1(centroid(u, v, s[u]));
      }
    }
  };
  decomposition1(0);

  int timer = 0;
  vector<pair<int, int>> vs;
  vector<int> tin(n), tout(n), par(n);
  function<void(int, int, int)> dfs = [&] (int v, int p, int dst) {
    par[v] = p;
    tin[v] = timer++;
    vs.emplace_back(dst, v);
    for (auto &u : g[v]) {
      if (u != p) {
        dfs(u, v, dst + 1);
      }
    }
    tout[v] = timer;
  };

  const int inf = 1e9;

  int res = 0;
  vector<int> mdist(n, inf);
  function<void(int)> decomposition2 = [&] (int v) {
    used[v] = 1;
    sizes(v, -1);

    vs.clear();
    dfs(v, -1, 0);
    sort(vs.begin(), vs.end());

    auto can = [&] (int ver, int dst) -> bool {
      for (auto &[centroid, dist_to_centroid] : centroids[ver]) {
        if (dist_to_centroid + mdist[centroid] < d) {
          return false;
        }
      }
      return true;
    };

    int m = sz(vs), r = m, cnt = 0;
    rep(l, m) {
      while (r - 1 >= l && vs[r - 1].first >= max(vs[l].first, d - vs[l].first)) {
        r--;
        int ver = vs[r].second;
        int dst = vs[r].first;
        if (can(ver, dst)) {
          cnt++;
          for (auto &[centroid, dist_to_centroid] : centroids[ver]) {
            mdist[centroid] = min(mdist[centroid], dist_to_centroid);
          }
        }
      }
      if (l == r) {
        res = max(res, cnt);
        break;
      } else {
        res = max(res, cnt + can(vs[l].second, vs[l].first));
      }
    }

    for (auto &[vd, ver] : vs) {
      for (auto &[centroid, dist_to_centroid] : centroids[ver]) {
        mdist[centroid] = inf;
      }
    }

    for (auto &u : g[v]) {
      if (!used[u]) {
        decomposition2(centroid(u, v, s[u]));
      }
    }
  };

  used.assign(n, 0);
  decomposition2(0);

  cout << res;
}
 
signed main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  solve();
  return 0;
}

Subtask #1
11.0 / 11.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 0 ms 212 KB Output is correct
3 Correct 0 ms 212 KB Output is correct
4 Correct 0 ms 212 KB Output is correct
5 Correct 1 ms 212 KB Output is correct
6 Correct 1 ms 212 KB Output is correct
7 Correct 1 ms 212 KB Output is correct
8 Correct 1 ms 212 KB Output is correct
9 Correct 0 ms 212 KB Output is correct
10 Correct 1 ms 212 KB Output is correct
11 Correct 0 ms 212 KB Output is correct
12 Correct 1 ms 212 KB Output is correct
13 Correct 0 ms 212 KB Output is correct
14 Correct 0 ms 212 KB Output is correct
15 Correct 0 ms 212 KB Output is correct
16 Correct 0 ms 212 KB Output is correct
17 Correct 0 ms 212 KB Output is correct
18 Correct 0 ms 212 KB Output is correct
19 Correct 0 ms 212 KB Output is correct
20 Correct 0 ms 212 KB Output is correct

Subtask #2
40.0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 0 ms 212 KB Output is correct
3 Correct 0 ms 212 KB Output is correct
4 Correct 0 ms 212 KB Output is correct
5 Correct 1 ms 212 KB Output is correct
6 Correct 1 ms 212 KB Output is correct
7 Correct 1 ms 212 KB Output is correct
8 Correct 1 ms 212 KB Output is correct
9 Correct 0 ms 212 KB Output is correct
10 Correct 1 ms 212 KB Output is correct
11 Correct 0 ms 212 KB Output is correct
12 Correct 1 ms 212 KB Output is correct
13 Correct 0 ms 212 KB Output is correct
14 Correct 0 ms 212 KB Output is correct
15 Correct 0 ms 212 KB Output is correct
16 Correct 0 ms 212 KB Output is correct
17 Correct 0 ms 212 KB Output is correct
18 Correct 0 ms 212 KB Output is correct
19 Correct 0 ms 212 KB Output is correct
20 Correct 0 ms 212 KB Output is correct
21 Correct 234 ms 852 KB Output is correct
22 Correct 35 ms 340 KB Output is correct
23 Correct 35 ms 420 KB Output is correct
24 Correct 33 ms 340 KB Output is correct
25 Correct 159 ms 504 KB Output is correct
26 Correct 138 ms 468 KB Output is correct
27 Correct 137 ms 516 KB Output is correct
28 Correct 322 ms 608 KB Output is correct
29 Correct 334 ms 612 KB Output is correct
30 Correct 325 ms 616 KB Output is correct
31 Correct 349 ms 608 KB Output is correct
32 Correct 198 ms 596 KB Output is correct
33 Correct 185 ms 596 KB Output is correct
34 Correct 216 ms 596 KB Output is correct
35 Correct 199 ms 596 KB Output is correct
36 Correct 251 ms 596 KB Output is correct
37 Correct 237 ms 660 KB Output is correct
38 Correct 270 ms 724 KB Output is correct
39 Correct 291 ms 752 KB Output is correct
40 Correct 301 ms 852 KB Output is correct

Subtask #3
0 / 49.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 0 ms 212 KB Output is correct
3 Correct 0 ms 212 KB Output is correct
4 Correct 0 ms 212 KB Output is correct
5 Correct 1 ms 212 KB Output is correct
6 Correct 1 ms 212 KB Output is correct
7 Correct 1 ms 212 KB Output is correct
8 Correct 1 ms 212 KB Output is correct
9 Correct 0 ms 212 KB Output is correct
10 Correct 1 ms 212 KB Output is correct
11 Correct 0 ms 212 KB Output is correct
12 Correct 1 ms 212 KB Output is correct
13 Correct 0 ms 212 KB Output is correct
14 Correct 0 ms 212 KB Output is correct
15 Correct 0 ms 212 KB Output is correct
16 Correct 0 ms 212 KB Output is correct
17 Correct 0 ms 212 KB Output is correct
18 Correct 0 ms 212 KB Output is correct
19 Correct 0 ms 212 KB Output is correct
20 Correct 0 ms 212 KB Output is correct
21 Correct 234 ms 852 KB Output is correct
22 Correct 35 ms 340 KB Output is correct
23 Correct 35 ms 420 KB Output is correct
24 Correct 33 ms 340 KB Output is correct
25 Correct 159 ms 504 KB Output is correct
26 Correct 138 ms 468 KB Output is correct
27 Correct 137 ms 516 KB Output is correct
28 Correct 322 ms 608 KB Output is correct
29 Correct 334 ms 612 KB Output is correct
30 Correct 325 ms 616 KB Output is correct
31 Correct 349 ms 608 KB Output is correct
32 Correct 198 ms 596 KB Output is correct
33 Correct 185 ms 596 KB Output is correct
34 Correct 216 ms 596 KB Output is correct
35 Correct 199 ms 596 KB Output is correct
36 Correct 251 ms 596 KB Output is correct
37 Correct 237 ms 660 KB Output is correct
38 Correct 270 ms 724 KB Output is correct
39 Correct 291 ms 752 KB Output is correct
40 Correct 301 ms 852 KB Output is correct
41 Execution timed out 1096 ms 30784 KB Time limit exceeded
42 Halted 0 ms 0 KB -