結果
| 問題 |
No.3206 う し た ウ ニ 木 あ く ん 笑
|
| コンテスト | |
| ユーザー |
 Koi
|
| 提出日時 | 2025-07-18 22:30:46 |
| 言語 | PyPy3 (7.3.15) |
| 結果 |
AC
|
| 実行時間 | 1,410 ms / 3,000 ms |
| コード長 | 6,765 bytes |
| コンパイル時間 | 345 ms |
| コンパイル使用メモリ | 82,708 KB |
| 実行使用メモリ | 204,892 KB |
| 最終ジャッジ日時 | 2025-07-18 22:31:08 |
| 合計ジャッジ時間 | 20,886 ms |
|
ジャッジサーバーID （参考情報） |
judge2 / judge1 |
（要ログイン）
| ファイルパターン | 結果 |
|---|---|
| sample | AC * 2 |
| other | AC * 30 |
ソースコード
# https://github.com/tatyam-prime/SortedSet/blob/main/SortedMultiset.py
import math
from bisect import bisect_left, bisect_right
from typing import Generic, Iterable, Iterator, TypeVar
T = TypeVar('T')
class SortedMultiset(Generic[T]):
BUCKET_RATIO = 16
SPLIT_RATIO = 24
def __init__(self, a: Iterable[T] = []) -> None:
"Make a new SortedMultiset from iterable. / O(N) if sorted / O(N log N)"
a = list(a)
n = self.size = len(a)
if any(a[i] > a[i + 1] for i in range(n - 1)):
a.sort()
num_bucket = int(math.ceil(math.sqrt(n / self.BUCKET_RATIO)))
self.a = [a[n * i // num_bucket : n * (i + 1) // num_bucket] for i in range(num_bucket)]
def __iter__(self) -> Iterator[T]:
for i in self.a:
for j in i: yield j
def __reversed__(self) -> Iterator[T]:
for i in reversed(self.a):
for j in reversed(i): yield j
def __eq__(self, other) -> bool:
return list(self) == list(other)
def __len__(self) -> int:
return self.size
def __repr__(self) -> str:
return "SortedMultiset" + str(self.a)
def __str__(self) -> str:
s = str(list(self))
return "{" + s[1 : len(s) - 1] + "}"
def _position(self, x: T) -> tuple[list[T], int, int]:
"return the bucket, index of the bucket and position in which x should be. self must not be empty."
for i, a in enumerate(self.a):
if x <= a[-1]: break
return (a, i, bisect_left(a, x))
def __contains__(self, x: T) -> bool:
if self.size == 0: return False
a, _, i = self._position(x)
return i != len(a) and a[i] == x
def count(self, x: T) -> int:
"Count the number of x."
return self.index_right(x) - self.index(x)
def add(self, x: T) -> None:
"Add an element. / O(√N)"
if self.size == 0:
self.a = [[x]]
self.size = 1
return
a, b, i = self._position(x)
a.insert(i, x)
self.size += 1
if len(a) > len(self.a) * self.SPLIT_RATIO:
mid = len(a) >> 1
self.a[b:b+1] = [a[:mid], a[mid:]]
def _pop(self, a: list[T], b: int, i: int) -> T:
ans = a.pop(i)
self.size -= 1
if not a: del self.a[b]
return ans
def discard(self, x: T) -> bool:
"Remove an element and return True if removed. / O(√N)"
if self.size == 0: return False
a, b, i = self._position(x)
if i == len(a) or a[i] != x: return False
self._pop(a, b, i)
return True
def lt(self, x: T) -> T | None:
"Find the largest element < x, or None if it doesn't exist."
for a in reversed(self.a):
if a[0] < x:
return a[bisect_left(a, x) - 1]
def le(self, x: T) -> T | None:
"Find the largest element <= x, or None if it doesn't exist."
for a in reversed(self.a):
if a[0] <= x:
return a[bisect_right(a, x) - 1]
def gt(self, x: T) -> T | None:
"Find the smallest element > x, or None if it doesn't exist."
for a in self.a:
if a[-1] > x:
return a[bisect_right(a, x)]
def ge(self, x: T) -> T | None:
"Find the smallest element >= x, or None if it doesn't exist."
for a in self.a:
if a[-1] >= x:
return a[bisect_left(a, x)]
def __getitem__(self, i: int) -> T:
"Return the i-th element."
if i < 0:
for a in reversed(self.a):
i += len(a)
if i >= 0: return a[i]
else:
for a in self.a:
if i < len(a): return a[i]
i -= len(a)
raise IndexError
def pop(self, i: int = -1) -> T:
"Pop and return the i-th element."
if i < 0:
for b, a in enumerate(reversed(self.a)):
i += len(a)
if i >= 0: return self._pop(a, ~b, i)
else:
for b, a in enumerate(self.a):
if i < len(a): return self._pop(a, b, i)
i -= len(a)
raise IndexError
def index(self, x: T) -> int:
"Count the number of elements < x."
ans = 0
for a in self.a:
if a[-1] >= x:
return ans + bisect_left(a, x)
ans += len(a)
return ans
def index_right(self, x: T) -> int:
"Count the number of elements <= x."
ans = 0
for a in self.a:
if a[-1] > x:
return ans + bisect_right(a, x)
ans += len(a)
return ans
N = int(input())
Graph = [[] for _ in range(N)]
for _ in range(N - 1):
a, b = map(int, input().split())
a -= 1
b -= 1
Graph[a].append(b)
Graph[b].append(a)
done = [0] * N
Q = [~0, 0] # 根をスタックに追加
ET = []
dp = [0] * N
L = [SortedMultiset([]) for _ in range(N)]
Parent = [-1 for _ in range(N)]
Children = [[] for _ in range(N)]
while Q:
i = Q.pop()
if i >= 0: # 行きがけの処理
done[i] = 1
ET.append(i)
for a in Graph[i][::-1]:
if done[a]: continue
Parent[a] = i
Children[i].append(a)
Q.append(~a) # 帰りがけの処理をスタックに追加
Q.append(a) # 行きがけの処理をスタックに追加
else: # 帰りがけの処理
i = ~i
ET.append(i)
for x in Children[i]:
L[i].add(dp[x])
if(len(L[i]) > 0):
dp[i] = L[i][-1] + 1
else:
dp[i] = 1
# if(len(L[i]) >= 3):
# dp[i] = L[i][-1] + L[i][-2] + L[i][-3] + 1
# else:
# dp[i] = 0
# print(ET)
# print(L)
# print(dp)
Seen = [False] * N
s = 0
ans = 0
# for x in Graph[0]:
# ans = max(ans, dp[x])
for i in range(len(L[0])):
ans = max(ans, L[0][i] * (len(L[0]) - i) + 1)
# print(ans)
for i in range(1, len(ET) - 1):
x = ET[i]
if(not Seen[x]):
#pre -> x
Seen[x] = True
t = x
else:
#x -> Parent[x]
t = Parent[x]
#(sからtに交換)
L[s].discard(dp[t])
# if(len(L[s]) >= 3):
# dp[s] = L[s][-1] + L[s][-2] + L[s][-3] + 1
# else:
# dp[s] = 0
if(len(L[s]) > 0):
dp[s] = L[s][-1] + 1
else:
dp[s] = 1
L[t].add(dp[s])
if(len(L[t]) > 0):
dp[t] = L[t][-1] + 1
else:
dp[t] = 1
# print(s, t)
# print(L)
# print(dp)
# print(L[t])
# print()
for i in range(len(L[t])):
ans = max(ans, L[t][i] * (len(L[t]) - i) + 1)
s = t
if(ans == 0):
print(-1)
else:
print(ans)
# print(ans)