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답안 #559247

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
559247 2022-05-09T14:37:46 Z Sweezy Cat in a tree (BOI17_catinatree) C++17
51 / 100
 1000 ms 43536 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;
  debug(centroids);

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

    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;
}

Compilation message

catinatree.cpp: In function 'void solve()':
catinatree.cpp:9:20: warning: statement has no effect [-Wunused-value]
    9 | #define debug(...) 42
      |                    ^~
catinatree.cpp:100:3: note: in expansion of macro 'debug'
  100 |   debug(centroids);
      |   ^~~~~
catinatree.cpp: In lambda function:
catinatree.cpp:9:20: warning: statement has no effect [-Wunused-value]
    9 | #define debug(...) 42
      |                    ^~
catinatree.cpp:107:5: note: in expansion of macro 'debug'
  107 |     debug(v);
      |     ^~~~~

Subtask #1
11.0 / 11.0

# 결과 실행 시간 메모리 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 0 ms 212 KB Output is correct
6 Correct 0 ms 212 KB Output is correct
7 Correct 0 ms 212 KB Output is correct
8 Correct 0 ms 212 KB Output is correct
9 Correct 0 ms 212 KB Output is correct
10 Correct 0 ms 212 KB Output is correct
11 Correct 0 ms 212 KB Output is correct
12 Correct 0 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 1 ms 212 KB Output is correct
18 Correct 0 ms 212 KB Output is correct
19 Correct 1 ms 212 KB Output is correct
20 Correct 1 ms 212 KB Output is correct

Subtask #2
40.0 / 40.0

# 결과 실행 시간 메모리 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 0 ms 212 KB Output is correct
6 Correct 0 ms 212 KB Output is correct
7 Correct 0 ms 212 KB Output is correct
8 Correct 0 ms 212 KB Output is correct
9 Correct 0 ms 212 KB Output is correct
10 Correct 0 ms 212 KB Output is correct
11 Correct 0 ms 212 KB Output is correct
12 Correct 0 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 1 ms 212 KB Output is correct
18 Correct 0 ms 212 KB Output is correct
19 Correct 1 ms 212 KB Output is correct
20 Correct 1 ms 212 KB Output is correct
21 Correct 225 ms 1108 KB Output is correct
22 Correct 34 ms 340 KB Output is correct
23 Correct 32 ms 468 KB Output is correct
24 Correct 30 ms 340 KB Output is correct
25 Correct 151 ms 596 KB Output is correct
26 Correct 138 ms 716 KB Output is correct
27 Correct 131 ms 628 KB Output is correct
28 Correct 292 ms 896 KB Output is correct
29 Correct 351 ms 844 KB Output is correct
30 Correct 298 ms 724 KB Output is correct
31 Correct 309 ms 844 KB Output is correct
32 Correct 183 ms 740 KB Output is correct
33 Correct 165 ms 724 KB Output is correct
34 Correct 185 ms 732 KB Output is correct
35 Correct 177 ms 724 KB Output is correct
36 Correct 209 ms 724 KB Output is correct
37 Correct 228 ms 972 KB Output is correct
38 Correct 258 ms 964 KB Output is correct
39 Correct 258 ms 992 KB Output is correct
40 Correct 265 ms 1136 KB Output is correct

Subtask #3
0 / 49.0

# 결과 실행 시간 메모리 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 0 ms 212 KB Output is correct
6 Correct 0 ms 212 KB Output is correct
7 Correct 0 ms 212 KB Output is correct
8 Correct 0 ms 212 KB Output is correct
9 Correct 0 ms 212 KB Output is correct
10 Correct 0 ms 212 KB Output is correct
11 Correct 0 ms 212 KB Output is correct
12 Correct 0 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 1 ms 212 KB Output is correct
18 Correct 0 ms 212 KB Output is correct
19 Correct 1 ms 212 KB Output is correct
20 Correct 1 ms 212 KB Output is correct
21 Correct 225 ms 1108 KB Output is correct
22 Correct 34 ms 340 KB Output is correct
23 Correct 32 ms 468 KB Output is correct
24 Correct 30 ms 340 KB Output is correct
25 Correct 151 ms 596 KB Output is correct
26 Correct 138 ms 716 KB Output is correct
27 Correct 131 ms 628 KB Output is correct
28 Correct 292 ms 896 KB Output is correct
29 Correct 351 ms 844 KB Output is correct
30 Correct 298 ms 724 KB Output is correct
31 Correct 309 ms 844 KB Output is correct
32 Correct 183 ms 740 KB Output is correct
33 Correct 165 ms 724 KB Output is correct
34 Correct 185 ms 732 KB Output is correct
35 Correct 177 ms 724 KB Output is correct
36 Correct 209 ms 724 KB Output is correct
37 Correct 228 ms 972 KB Output is correct
38 Correct 258 ms 964 KB Output is correct
39 Correct 258 ms 992 KB Output is correct
40 Correct 265 ms 1136 KB Output is correct
41 Execution timed out 1088 ms 43536 KB Time limit exceeded
42 Halted 0 ms 0 KB -