結果

問題 No.778 クリスマスツリー
ユーザー lloyzlloyz
提出日時 2023-10-30 00:13:16
言語 PyPy3
(7.3.15)
結果
AC  
実行時間 1,294 ms / 2,000 ms
コード長 4,614 bytes
コンパイル時間 450 ms
コンパイル使用メモリ 81,872 KB
実行使用メモリ 412,256 KB
最終ジャッジ日時 2024-09-25 17:00:14
合計ジャッジ時間 10,060 ms
ジャッジサーバーID
（参考情報） 		judge1 / judge2
このコードへのチャレンジ
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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 63 ms
67,952 KB
testcase_01 AC 64 ms
68,828 KB
testcase_02 AC 63 ms
68,480 KB
testcase_03 AC 64 ms
68,192 KB
testcase_04 AC 65 ms
67,944 KB
testcase_05 AC 63 ms
68,284 KB
testcase_06 AC 1,294 ms
412,256 KB
testcase_07 AC 266 ms
124,616 KB
testcase_08 AC 1,244 ms
226,852 KB
testcase_09 AC 1,101 ms
135,684 KB
testcase_10 AC 1,059 ms
135,592 KB
testcase_11 AC 447 ms
135,752 KB
testcase_12 AC 467 ms
135,084 KB
testcase_13 AC 473 ms
134,208 KB
testcase_14 AC 1,265 ms
412,204 KB
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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, insort
from typing import Generic, Iterable, Iterator, TypeVar, Union, List
T = TypeVar('T')
 
class SortedMultiset(Generic[T]):
    BUCKET_RATIO = 50
    REBUILD_RATIO = 170
 
    def _build(self, a=None) -> None:
        "Evenly divide `a` into buckets."
        if a is None: a = list(self)
        size = self.size = len(a)
        bucket_size = int(math.ceil(math.sqrt(size / self.BUCKET_RATIO)))
        self.a = [a[size * i // bucket_size : size * (i + 1) // bucket_size] for i in range(bucket_size)]
    
    def __init__(self, a: Iterable[T] = []) -> None:
        "Make a new SortedMultiset from iterable. / O(N) if sorted / O(N log N)"
        a = list(a)
        if not all(a[i] <= a[i + 1] for i in range(len(a) - 1)):
            a = sorted(a)
        self._build(a)
 
    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 __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 _find_bucket(self, x: T) -> List[T]:
        "Find the bucket which should contain x. self must not be empty."
        for a in self.a:
            if x <= a[-1]: return a
        return a
 
    def __contains__(self, x: T) -> bool:
        if self.size == 0: return False
        a = self._find_bucket(x)
        i = bisect_left(a, 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 = self._find_bucket(x)
        insort(a, x)
        self.size += 1
        if len(a) > len(self.a) * self.REBUILD_RATIO:
            self._build()
 
    def discard(self, x: T) -> bool:
        "Remove an element and return True if removed. / O(√N)"
        if self.size == 0: return False
        a = self._find_bucket(x)
        i = bisect_left(a, x)
        if i == len(a) or a[i] != x: return False
        a.pop(i)
        self.size -= 1
        if len(a) == 0: self._build()
        return True
 
    def lt(self, x: T) -> Union[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) -> Union[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) -> Union[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) -> Union[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, x: int) -> T:
        "Return the x-th element, or IndexError if it doesn't exist."
        if x < 0: x += self.size
        if x < 0: raise IndexError
        for a in self.a:
            if x < len(a): return a[x]
            x -= 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

from collections import defaultdict
import sys
sys.setrecursionlimit(10**6)

n = int(input())
A = list(map(int, input().split()))

G = defaultdict(list)
for i in range(n - 1):
    p = A[i]
    G[p].append(i + 1)
ans = 0

seen = SortedMultiset()
def rec(ci):
    global ans
    ans += seen.index(ci)
    seen.add(ci)
    for np in G[ci]:
        rec(np)
    seen.discard(ci)

rec(0)
print(ans)
0