結果

問題 No.3206 う し た ウ ニ 木 あ く ん 笑
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
このコードへのチャレンジ
(要ログイン)
ファイルパターン 結果
sample AC * 2
other AC * 30
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ソースコード

diff #

# 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)
0