oj.uz

Submission #559292

# Submission time Handle Problem Language Result Execution time Memory
559292 2022-05-09T15:05:44 Z Sweezy Cat in a tree (BOI17_catinatree) C++17
100 / 100
 845 ms 68316 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];
vector<pair<int, int>> centroids[N];
int s[N], mdist[N], used[N], res, d, m;

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]));
    }
  }
}

int vis[N], dis[N], q[N], from, to, vs[N];

void decomposition2(int v) {
  used[v] = 1;
  sizes(v, -1);

  m = 0;
  from = 0;
  to = 1;
  dis[v] = 0;
  q[0] = v;
  while (from != to) {
    int ver = q[from++];
    vs[m++] = ver;
    vis[ver] = 1;
    for (auto &u : g[ver]) {
      if (!used[u] && !vis[u]) {
        dis[u] = dis[ver] + 1;
        q[to++] = u;
        vis[u] = 1;
      }
    }
  }


// [v, vs]: 0 {(0, 0), (1, 1), (1, 2), (2, 3)}
// [v, vs]: 1 {(0, 1), (1, 0), (1, 3), (2, 2)}
// [v, vs]: 3 {(0, 3), (1, 1), (2, 0), (3, 2)}
// [v, vs]: 2 {(0, 2), (1, 0), (2, 1), (3, 3)}

  // debug(v);
  // for (int i = 0; i < m; i++) {
  //   cout << vs[i] << ' ' << dis[vs[i]] << '\n';
  // }

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

  int r = m, cnt = 0;
  rep(l, m) {
    while (r - 1 >= l && dis[vs[r - 1]] >= max(dis[vs[l]], d - dis[vs[l]])) {
      r--;
      int ver = vs[r];
      if (can(ver)) {
        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]));
    }
  }

  for (int i = 0; i < m; i++) {
    for (auto &[centroid, dist_to_centroid] : centroids[vs[i]]) {
      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);
  }
  
  sizes(0, -1);
  decomposition1(centroid(0, -1, n));

  fill(used, used + N, 0);
  sizes(0, -1);
  decomposition2(centroid(0, -1, n));

  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 7 ms 11220 KB Output is correct
2 Correct 6 ms 11220 KB Output is correct
3 Correct 6 ms 11220 KB Output is correct
4 Correct 7 ms 11296 KB Output is correct
5 Correct 6 ms 11220 KB Output is correct
6 Correct 6 ms 11220 KB Output is correct
7 Correct 8 ms 11220 KB Output is correct
8 Correct 7 ms 11220 KB Output is correct
9 Correct 6 ms 11312 KB Output is correct
10 Correct 6 ms 11288 KB Output is correct
11 Correct 7 ms 11220 KB Output is correct
12 Correct 6 ms 11192 KB Output is correct
13 Correct 8 ms 11300 KB Output is correct
14 Correct 6 ms 11220 KB Output is correct
15 Correct 7 ms 11308 KB Output is correct
16 Correct 7 ms 11308 KB Output is correct
17 Correct 7 ms 11220 KB Output is correct
18 Correct 6 ms 11220 KB Output is correct
19 Correct 7 ms 11272 KB Output is correct
20 Correct 7 ms 11220 KB Output is correct

Subtask #2
40.0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 7 ms 11220 KB Output is correct
2 Correct 6 ms 11220 KB Output is correct
3 Correct 6 ms 11220 KB Output is correct
4 Correct 7 ms 11296 KB Output is correct
5 Correct 6 ms 11220 KB Output is correct
6 Correct 6 ms 11220 KB Output is correct
7 Correct 8 ms 11220 KB Output is correct
8 Correct 7 ms 11220 KB Output is correct
9 Correct 6 ms 11312 KB Output is correct
10 Correct 6 ms 11288 KB Output is correct
11 Correct 7 ms 11220 KB Output is correct
12 Correct 6 ms 11192 KB Output is correct
13 Correct 8 ms 11300 KB Output is correct
14 Correct 6 ms 11220 KB Output is correct
15 Correct 7 ms 11308 KB Output is correct
16 Correct 7 ms 11308 KB Output is correct
17 Correct 7 ms 11220 KB Output is correct
18 Correct 6 ms 11220 KB Output is correct
19 Correct 7 ms 11272 KB Output is correct
20 Correct 7 ms 11220 KB Output is correct
21 Correct 9 ms 11604 KB Output is correct
22 Correct 11 ms 11348 KB Output is correct
23 Correct 7 ms 11380 KB Output is correct
24 Correct 7 ms 11384 KB Output is correct
25 Correct 7 ms 11348 KB Output is correct
26 Correct 7 ms 11348 KB Output is correct
27 Correct 8 ms 11348 KB Output is correct
28 Correct 8 ms 11476 KB Output is correct
29 Correct 9 ms 11476 KB Output is correct
30 Correct 9 ms 11476 KB Output is correct
31 Correct 8 ms 11476 KB Output is correct
32 Correct 7 ms 11456 KB Output is correct
33 Correct 7 ms 11476 KB Output is correct
34 Correct 8 ms 11476 KB Output is correct
35 Correct 8 ms 11504 KB Output is correct
36 Correct 7 ms 11448 KB Output is correct
37 Correct 8 ms 11468 KB Output is correct
38 Correct 8 ms 11580 KB Output is correct
39 Correct 8 ms 11476 KB Output is correct
40 Correct 10 ms 11596 KB Output is correct

Subtask #3
49.0 / 49.0

# Verdict Execution time Memory Grader output
1 Correct 7 ms 11220 KB Output is correct
2 Correct 6 ms 11220 KB Output is correct
3 Correct 6 ms 11220 KB Output is correct
4 Correct 7 ms 11296 KB Output is correct
5 Correct 6 ms 11220 KB Output is correct
6 Correct 6 ms 11220 KB Output is correct
7 Correct 8 ms 11220 KB Output is correct
8 Correct 7 ms 11220 KB Output is correct
9 Correct 6 ms 11312 KB Output is correct
10 Correct 6 ms 11288 KB Output is correct
11 Correct 7 ms 11220 KB Output is correct
12 Correct 6 ms 11192 KB Output is correct
13 Correct 8 ms 11300 KB Output is correct
14 Correct 6 ms 11220 KB Output is correct
15 Correct 7 ms 11308 KB Output is correct
16 Correct 7 ms 11308 KB Output is correct
17 Correct 7 ms 11220 KB Output is correct
18 Correct 6 ms 11220 KB Output is correct
19 Correct 7 ms 11272 KB Output is correct
20 Correct 7 ms 11220 KB Output is correct
21 Correct 9 ms 11604 KB Output is correct
22 Correct 11 ms 11348 KB Output is correct
23 Correct 7 ms 11380 KB Output is correct
24 Correct 7 ms 11384 KB Output is correct
25 Correct 7 ms 11348 KB Output is correct
26 Correct 7 ms 11348 KB Output is correct
27 Correct 8 ms 11348 KB Output is correct
28 Correct 8 ms 11476 KB Output is correct
29 Correct 9 ms 11476 KB Output is correct
30 Correct 9 ms 11476 KB Output is correct
31 Correct 8 ms 11476 KB Output is correct
32 Correct 7 ms 11456 KB Output is correct
33 Correct 7 ms 11476 KB Output is correct
34 Correct 8 ms 11476 KB Output is correct
35 Correct 8 ms 11504 KB Output is correct
36 Correct 7 ms 11448 KB Output is correct
37 Correct 8 ms 11468 KB Output is correct
38 Correct 8 ms 11580 KB Output is correct
39 Correct 8 ms 11476 KB Output is correct
40 Correct 10 ms 11596 KB Output is correct
41 Correct 174 ms 29960 KB Output is correct
42 Correct 353 ms 28852 KB Output is correct
43 Correct 296 ms 29404 KB Output is correct
44 Correct 337 ms 29196 KB Output is correct
45 Correct 331 ms 29072 KB Output is correct
46 Correct 845 ms 46904 KB Output is correct
47 Correct 818 ms 47784 KB Output is correct
48 Correct 832 ms 48076 KB Output is correct
49 Correct 825 ms 48212 KB Output is correct
50 Correct 184 ms 25348 KB Output is correct
51 Correct 183 ms 25736 KB Output is correct
52 Correct 180 ms 25524 KB Output is correct
53 Correct 458 ms 40848 KB Output is correct
54 Correct 486 ms 40244 KB Output is correct
55 Correct 498 ms 40296 KB Output is correct
56 Correct 12 ms 11732 KB Output is correct
57 Correct 32 ms 16672 KB Output is correct
58 Correct 173 ms 40224 KB Output is correct
59 Correct 600 ms 68316 KB Output is correct
60 Correct 158 ms 31448 KB Output is correct
61 Correct 276 ms 38048 KB Output is correct