oj.uz

Submission #559264

# Submission time Handle Problem Language Result Execution time Memory
559264 2022-05-09T14:49:20 Z Sweezy Cat in a tree (BOI17_catinatree) C++17
51 / 100
 1000 ms 38588 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())

const int N = 2e5 + 5;
const int inf = 1e9;

vector<int> g[N];
int s[N], mdist[N], used[N], res, d;
vector<pair<int, int>> centroids[N], vs;

void 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];
    }
  }
}

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;
}

void 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);
    }
  }
}

void 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]));
    }
  }
}

void dfs(int v, int p, int dst) {
  vs.emplace_back(dst, v);
  for (auto &u : g[v]) {
    if (u != p) {
      dfs(u, v, dst + 1);
    }
  }
}

void 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]));
    }
  }
}

void solve() {
  fill(mdist, mdist + N, inf);

  int n;
  cin >> n >> d;
 
  if (d > n - 1) {
    cout << 1;
    return;
  }
 
  if (d == 0) {
    cout << n;
    return;
  }
 
  reps(i, 1, n) {
    int p;
    cin >> p;
    g[p].push_back(i);
    g[i].push_back(p);
  }
  
  decomposition1(0);
  fill(used, used + 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 8 ms 12756 KB Output is correct
2 Correct 7 ms 12756 KB Output is correct
3 Correct 10 ms 12756 KB Output is correct
4 Correct 7 ms 12856 KB Output is correct
5 Correct 7 ms 12756 KB Output is correct
6 Correct 7 ms 12756 KB Output is correct
7 Correct 8 ms 12756 KB Output is correct
8 Correct 8 ms 12756 KB Output is correct
9 Correct 8 ms 12756 KB Output is correct
10 Correct 8 ms 12840 KB Output is correct
11 Correct 9 ms 12756 KB Output is correct
12 Correct 8 ms 12756 KB Output is correct
13 Correct 9 ms 12756 KB Output is correct
14 Correct 9 ms 12840 KB Output is correct
15 Correct 7 ms 12756 KB Output is correct
16 Correct 8 ms 12756 KB Output is correct
17 Correct 8 ms 12852 KB Output is correct
18 Correct 8 ms 12756 KB Output is correct
19 Correct 9 ms 12764 KB Output is correct
20 Correct 8 ms 12776 KB Output is correct

Subtask #2
40.0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 8 ms 12756 KB Output is correct
2 Correct 7 ms 12756 KB Output is correct
3 Correct 10 ms 12756 KB Output is correct
4 Correct 7 ms 12856 KB Output is correct
5 Correct 7 ms 12756 KB Output is correct
6 Correct 7 ms 12756 KB Output is correct
7 Correct 8 ms 12756 KB Output is correct
8 Correct 8 ms 12756 KB Output is correct
9 Correct 8 ms 12756 KB Output is correct
10 Correct 8 ms 12840 KB Output is correct
11 Correct 9 ms 12756 KB Output is correct
12 Correct 8 ms 12756 KB Output is correct
13 Correct 9 ms 12756 KB Output is correct
14 Correct 9 ms 12840 KB Output is correct
15 Correct 7 ms 12756 KB Output is correct
16 Correct 8 ms 12756 KB Output is correct
17 Correct 8 ms 12852 KB Output is correct
18 Correct 8 ms 12756 KB Output is correct
19 Correct 9 ms 12764 KB Output is correct
20 Correct 8 ms 12776 KB Output is correct
21 Correct 231 ms 13460 KB Output is correct
22 Correct 44 ms 12884 KB Output is correct
23 Correct 38 ms 12920 KB Output is correct
24 Correct 37 ms 12836 KB Output is correct
25 Correct 147 ms 13064 KB Output is correct
26 Correct 139 ms 13060 KB Output is correct
27 Correct 136 ms 13012 KB Output is correct
28 Correct 291 ms 13188 KB Output is correct
29 Correct 337 ms 13176 KB Output is correct
30 Correct 295 ms 13216 KB Output is correct
31 Correct 307 ms 13192 KB Output is correct
32 Correct 163 ms 13128 KB Output is correct
33 Correct 137 ms 13140 KB Output is correct
34 Correct 177 ms 13140 KB Output is correct
35 Correct 159 ms 13140 KB Output is correct
36 Correct 204 ms 13184 KB Output is correct
37 Correct 208 ms 13248 KB Output is correct
38 Correct 229 ms 13364 KB Output is correct
39 Correct 249 ms 13396 KB Output is correct
40 Correct 245 ms 13464 KB Output is correct

Subtask #3
0 / 49.0

# Verdict Execution time Memory Grader output
1 Correct 8 ms 12756 KB Output is correct
2 Correct 7 ms 12756 KB Output is correct
3 Correct 10 ms 12756 KB Output is correct
4 Correct 7 ms 12856 KB Output is correct
5 Correct 7 ms 12756 KB Output is correct
6 Correct 7 ms 12756 KB Output is correct
7 Correct 8 ms 12756 KB Output is correct
8 Correct 8 ms 12756 KB Output is correct
9 Correct 8 ms 12756 KB Output is correct
10 Correct 8 ms 12840 KB Output is correct
11 Correct 9 ms 12756 KB Output is correct
12 Correct 8 ms 12756 KB Output is correct
13 Correct 9 ms 12756 KB Output is correct
14 Correct 9 ms 12840 KB Output is correct
15 Correct 7 ms 12756 KB Output is correct
16 Correct 8 ms 12756 KB Output is correct
17 Correct 8 ms 12852 KB Output is correct
18 Correct 8 ms 12756 KB Output is correct
19 Correct 9 ms 12764 KB Output is correct
20 Correct 8 ms 12776 KB Output is correct
21 Correct 231 ms 13460 KB Output is correct
22 Correct 44 ms 12884 KB Output is correct
23 Correct 38 ms 12920 KB Output is correct
24 Correct 37 ms 12836 KB Output is correct
25 Correct 147 ms 13064 KB Output is correct
26 Correct 139 ms 13060 KB Output is correct
27 Correct 136 ms 13012 KB Output is correct
28 Correct 291 ms 13188 KB Output is correct
29 Correct 337 ms 13176 KB Output is correct
30 Correct 295 ms 13216 KB Output is correct
31 Correct 307 ms 13192 KB Output is correct
32 Correct 163 ms 13128 KB Output is correct
33 Correct 137 ms 13140 KB Output is correct
34 Correct 177 ms 13140 KB Output is correct
35 Correct 159 ms 13140 KB Output is correct
36 Correct 204 ms 13184 KB Output is correct
37 Correct 208 ms 13248 KB Output is correct
38 Correct 229 ms 13364 KB Output is correct
39 Correct 249 ms 13396 KB Output is correct
40 Correct 245 ms 13464 KB Output is correct
41 Execution timed out 1089 ms 38588 KB Time limit exceeded
42 Halted 0 ms 0 KB -