oj.uz

Submission #559267

# Submission time Handle Problem Language Result Execution time Memory
559267 2022-05-09T14:49:55 Z Sweezy Cat in a tree (BOI17_catinatree) C++17
51 / 100
 1000 ms 29104 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 11220 KB Output is correct
2 Correct 6 ms 11220 KB Output is correct
3 Correct 5 ms 11220 KB Output is correct
4 Correct 6 ms 11220 KB Output is correct
5 Correct 6 ms 11220 KB Output is correct
6 Correct 6 ms 11220 KB Output is correct
7 Correct 6 ms 11276 KB Output is correct
8 Correct 5 ms 11220 KB Output is correct
9 Correct 6 ms 11200 KB Output is correct
10 Correct 6 ms 11220 KB Output is correct
11 Correct 6 ms 11220 KB Output is correct
12 Correct 6 ms 11220 KB Output is correct
13 Correct 6 ms 11220 KB Output is correct
14 Correct 7 ms 11220 KB Output is correct
15 Correct 6 ms 11220 KB Output is correct
16 Correct 7 ms 11160 KB Output is correct
17 Correct 6 ms 11168 KB Output is correct
18 Correct 6 ms 11220 KB Output is correct
19 Correct 8 ms 11236 KB Output is correct
20 Correct 6 ms 11220 KB Output is correct

Subtask #2
40.0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 8 ms 11220 KB Output is correct
2 Correct 6 ms 11220 KB Output is correct
3 Correct 5 ms 11220 KB Output is correct
4 Correct 6 ms 11220 KB Output is correct
5 Correct 6 ms 11220 KB Output is correct
6 Correct 6 ms 11220 KB Output is correct
7 Correct 6 ms 11276 KB Output is correct
8 Correct 5 ms 11220 KB Output is correct
9 Correct 6 ms 11200 KB Output is correct
10 Correct 6 ms 11220 KB Output is correct
11 Correct 6 ms 11220 KB Output is correct
12 Correct 6 ms 11220 KB Output is correct
13 Correct 6 ms 11220 KB Output is correct
14 Correct 7 ms 11220 KB Output is correct
15 Correct 6 ms 11220 KB Output is correct
16 Correct 7 ms 11160 KB Output is correct
17 Correct 6 ms 11168 KB Output is correct
18 Correct 6 ms 11220 KB Output is correct
19 Correct 8 ms 11236 KB Output is correct
20 Correct 6 ms 11220 KB Output is correct
21 Correct 201 ms 11664 KB Output is correct
22 Correct 36 ms 11348 KB Output is correct
23 Correct 32 ms 11348 KB Output is correct
24 Correct 34 ms 11336 KB Output is correct
25 Correct 134 ms 11396 KB Output is correct
26 Correct 139 ms 11404 KB Output is correct
27 Correct 125 ms 11400 KB Output is correct
28 Correct 254 ms 11488 KB Output is correct
29 Correct 294 ms 11500 KB Output is correct
30 Correct 279 ms 11504 KB Output is correct
31 Correct 277 ms 11492 KB Output is correct
32 Correct 168 ms 11488 KB Output is correct
33 Correct 147 ms 11476 KB Output is correct
34 Correct 154 ms 11472 KB Output is correct
35 Correct 153 ms 11472 KB Output is correct
36 Correct 219 ms 11488 KB Output is correct
37 Correct 195 ms 11532 KB Output is correct
38 Correct 222 ms 11560 KB Output is correct
39 Correct 252 ms 11584 KB Output is correct
40 Correct 240 ms 11664 KB Output is correct

Subtask #3
0 / 49.0

# Verdict Execution time Memory Grader output
1 Correct 8 ms 11220 KB Output is correct
2 Correct 6 ms 11220 KB Output is correct
3 Correct 5 ms 11220 KB Output is correct
4 Correct 6 ms 11220 KB Output is correct
5 Correct 6 ms 11220 KB Output is correct
6 Correct 6 ms 11220 KB Output is correct
7 Correct 6 ms 11276 KB Output is correct
8 Correct 5 ms 11220 KB Output is correct
9 Correct 6 ms 11200 KB Output is correct
10 Correct 6 ms 11220 KB Output is correct
11 Correct 6 ms 11220 KB Output is correct
12 Correct 6 ms 11220 KB Output is correct
13 Correct 6 ms 11220 KB Output is correct
14 Correct 7 ms 11220 KB Output is correct
15 Correct 6 ms 11220 KB Output is correct
16 Correct 7 ms 11160 KB Output is correct
17 Correct 6 ms 11168 KB Output is correct
18 Correct 6 ms 11220 KB Output is correct
19 Correct 8 ms 11236 KB Output is correct
20 Correct 6 ms 11220 KB Output is correct
21 Correct 201 ms 11664 KB Output is correct
22 Correct 36 ms 11348 KB Output is correct
23 Correct 32 ms 11348 KB Output is correct
24 Correct 34 ms 11336 KB Output is correct
25 Correct 134 ms 11396 KB Output is correct
26 Correct 139 ms 11404 KB Output is correct
27 Correct 125 ms 11400 KB Output is correct
28 Correct 254 ms 11488 KB Output is correct
29 Correct 294 ms 11500 KB Output is correct
30 Correct 279 ms 11504 KB Output is correct
31 Correct 277 ms 11492 KB Output is correct
32 Correct 168 ms 11488 KB Output is correct
33 Correct 147 ms 11476 KB Output is correct
34 Correct 154 ms 11472 KB Output is correct
35 Correct 153 ms 11472 KB Output is correct
36 Correct 219 ms 11488 KB Output is correct
37 Correct 195 ms 11532 KB Output is correct
38 Correct 222 ms 11560 KB Output is correct
39 Correct 252 ms 11584 KB Output is correct
40 Correct 240 ms 11664 KB Output is correct
41 Execution timed out 1080 ms 29104 KB Time limit exceeded
42 Halted 0 ms 0 KB -