結果

問題 No.1424 Ultrapalindrome
ユーザー stoqstoq
提出日時 2021-03-12 23:06:44
言語 C++17
(gcc 12.3.0 + boost 1.83.0)
結果
WA  
実行時間 -
コード長 5,939 bytes
コンパイル時間 2,879 ms
コンパイル使用メモリ 224,568 KB
実行使用メモリ 30,592 KB
最終ジャッジ日時 2024-10-14 13:41:54
合計ジャッジ時間 4,940 ms
ジャッジサーバーID
（参考情報） 		judge2 / judge5
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テストケース

テストケース表示
入力 結果 実行時間
実行使用メモリ
testcase_00 AC 2 ms
5,248 KB
testcase_01 AC 2 ms
5,248 KB
testcase_02 AC 2 ms
5,248 KB
testcase_03 AC 2 ms
5,248 KB
testcase_04 AC 2 ms
5,248 KB
testcase_05 AC 2 ms
5,248 KB
testcase_06 AC 2 ms
5,248 KB
testcase_07 AC 2 ms
5,248 KB
testcase_08 WA -
testcase_09 AC 68 ms
20,864 KB
testcase_10 AC 70 ms
20,992 KB
testcase_11 AC 50 ms
15,744 KB
testcase_12 AC 52 ms
19,968 KB
testcase_13 AC 17 ms
7,936 KB
testcase_14 AC 45 ms
17,024 KB
testcase_15 AC 2 ms
5,248 KB
testcase_16 AC 34 ms
13,952 KB
testcase_17 AC 41 ms
16,256 KB
testcase_18 AC 33 ms
11,904 KB
testcase_19 AC 58 ms
16,256 KB
testcase_20 AC 13 ms
6,400 KB
testcase_21 AC 45 ms
13,952 KB
testcase_22 AC 26 ms
9,856 KB
testcase_23 AC 6 ms
5,248 KB
testcase_24 AC 11 ms
6,272 KB
testcase_25 AC 11 ms
6,016 KB
testcase_26 AC 71 ms
19,072 KB
testcase_27 WA -
testcase_28 AC 33 ms
11,776 KB
testcase_29 WA -
testcase_30 AC 63 ms
25,908 KB
testcase_31 AC 65 ms
25,776 KB
権限があれば一括ダウンロードができます

ソースコード

diff # 

#define MOD_TYPE 1

#pragma region Macros

#include <bits/stdc++.h>
using namespace std;

#if 0
#include <boost/multiprecision/cpp_int.hpp>
#include <boost/multiprecision/cpp_dec_float.hpp>
using Int = boost::multiprecision::cpp_int;
using lld = boost::multiprecision::cpp_dec_float_100;
#endif
#if 1
#pragma GCC target("avx2")
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
#endif
using ll = long long int;
using ld = long double;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
using pld = pair<ld, ld>;
template <typename Q_type>
using smaller_queue = priority_queue<Q_type, vector<Q_type>, greater<Q_type>>;

constexpr ll MOD = (MOD_TYPE == 1 ? (ll)(1e9 + 7) : 998244353);
constexpr int INF = (int)1e9 + 10;
constexpr ll LINF = (ll)4e18;
constexpr double PI = acos(-1.0);
constexpr double EPS = 1e-7;
constexpr int Dx[] = {0, 0, -1, 1, -1, 1, -1, 1, 0};
constexpr int Dy[] = {1, -1, 0, 0, -1, -1, 1, 1, 0};

#define REP(i, m, n) for (ll i = m; i < (ll)(n); ++i)
#define rep(i, n) REP(i, 0, n)
#define REPI(i, m, n) for (int i = m; i < (int)(n); ++i)
#define repi(i, n) REPI(i, 0, n)
#define MP make_pair
#define MT make_tuple
#define YES(n) cout << ((n) ? "YES" : "NO") << "\n"
#define Yes(n) cout << ((n) ? "Yes" : "No") << "\n"
#define possible(n) cout << ((n) ? "possible" : "impossible") << "\n"
#define Possible(n) cout << ((n) ? "Possible" : "Impossible") << "\n"
#define all(v) v.begin(), v.end()
#define NP(v) next_permutation(all(v))
#define dbg(x) cerr << #x << ":" << x << "\n";

struct io_init
{
  io_init()
  {
    cin.tie(0);
    ios::sync_with_stdio(false);
    cout << setprecision(30) << setiosflags(ios::fixed);
  };
} io_init;
template <typename T>
inline bool chmin(T &a, T b)
{
  if (a > b)
  {
    a = b;
    return true;
  }
  return false;
}
template <typename T>
inline bool chmax(T &a, T b)
{
  if (a < b)
  {
    a = b;
    return true;
  }
  return false;
}
inline ll CEIL(ll a, ll b)
{
  return (a + b - 1) / b;
}
template <typename A, size_t N, typename T>
inline void Fill(A (&array)[N], const T &val)
{
  fill((T *)array, (T *)(array + N), val);
}
template <typename T, typename U>
constexpr istream &operator>>(istream &is, pair<T, U> &p) noexcept
{
  is >> p.first >> p.second;
  return is;
}
template <typename T, typename U>
constexpr ostream &operator<<(ostream &os, pair<T, U> &p) noexcept
{
  os << p.first << " " << p.second;
  return os;
}
#pragma endregion

template <typename T = ll>
struct Tree
{
  int V;
  using P = pair<int, ll>;
  vector<vector<P>> E;
  vector<int> par;
  vector<int> depth;
  vector<int> sub;
  vector<T> dist;
  vector<vector<int>> par_double;

  Tree(int V_) : V(V_)
  {
    E.resize(V);
    depth.resize(V);
    dist.resize(V);
    sub.resize(V);
  }

  void add_E(int a, int b, T w = T(1), bool direction = false)
  {
    E[a].push_back(make_pair(b, w));
    if (!direction)
      E[b].push_back(make_pair(a, w));
  }

  int dfs(int p, int d, T w)
  {
    sub[p] = 1;
    for (auto pi : E[p])
    {
      int v = pi.first;
      if (par[p] == v)
        continue;
      par[v] = p;
      depth[v] = d + 1;
      dist[v] = w + pi.second;
      sub[p] += dfs(v, depth[v], dist[v]);
    }
    return sub[p];
  }

  void make_tree(int root = 0)
  {
    calculated = false;
    par.assign(V, -1);
    par_double.assign(V, vector<int>(25));
    depth[root] = 0;
    dist[root] = T(0);
    dfs(root, 0, 0);
  }

  bool calculated;
  void calc_double()
  {
    for (int i = 0; i < V; i++)
      par_double[i][0] = par[i];

    for (int k = 0; k < 24; k++)
    {
      for (int i = 0; i < V; i++)
      {
        if (par_double[i][k] == -1)
          par_double[i][k + 1] = -1;
        else
          par_double[i][k + 1] = par_double[par_double[i][k]][k];
      }
    }
  }

  int getLCA(int a, int b)
  {
    if (!calculated)
    {
      calc_double();
      calculated = true;
    }
    if (a == b)
      return a;
    if (depth[a] < depth[b])
      swap(a, b);
    for (int k = 24; k >= 0; k--)
    {
      if (par_double[a][k] != -1 && depth[par_double[a][k]] >= depth[b])
        a = par_double[a][k];
    }
    if (a == b)
      return a;
    for (int k = 24; k >= 0; k--)
    {
      if (par_double[a][k] != -1 && par_double[a][k] != par_double[b][k])
      {
        a = par_double[a][k];
        b = par_double[b][k];
      }
    }
    return par_double[a][0];
  }

  int length(int a, int b)
  {
    return depth[a] + depth[b] - 2 * depth[getLCA(a, b)];
  }

  int distance(int a, int b)
  {
    return dist[a] + dist[b] - 2 * dist[getLCA(a, b)];
  }

  T diameter(int &a, int &b)
  {
    T Max(-1);
    for (int i = 0; i < V; i++)
    {
      if (Max < distance(0, i))
        Max = distance(0, i), a = i;
    }
    for (int i = 0; i < V; i++)
    {
      if (Max < distance(a, i))
        Max = distance(a, i), b = i;
    }
    return Max;
  }

  T diameter()
  {
    int a, b;
    return diameter(a, b);
  }

  int diameter_l(int &a, int &b)
  {
    int Max = -1;
    for (int i = 0; i < V; i++)
    {
      if (Max < length(0, i))
        Max = length(0, i), a = i;
    }
    for (int i = 0; i < V; i++)
    {
      if (Max < length(a, i))
        Max = length(a, i), b = i;
    }
    return Max;
  }

  int diameter_l()
  {
    int a, b;
    return diameter_l(a, b);
  }
};

void solve()
{
  int n;
  cin >> n;
  Tree<int> tr(n);
  vector<int> cnt(n, 0);
  rep(i, n - 1)
  {
    int a, b;
    cin >> a >> b, a--, b--;
    cnt[a]++, cnt[b]++;
    tr.add_E(a, b);
  }

  vector<int> leaves;
  rep(i, n)
  {
    if (cnt[i] == 1)
    {
      leaves.push_back(i);
    }
  }
  if (leaves.size() == 2)
  {
    Yes(1);
    return;
  }
  tr.make_tree(leaves[0]);
  int d = tr.depth[leaves[1]];
  if (d % 2 == 1)
  {
    Yes(0);
    return;
  }
  int v = leaves[1];
  rep(i, d / 2) v = tr.par[v];
  for (auto l : leaves)
  {
    if (tr.distance(l, v) != d / 2)
    {
      Yes(0);
      return;
    }
  }
  Yes(1);
}

int main()
{

  solve();
}
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