結果

問題 No.1418 Sum of Sum of Subtree Size
コンテスト
ユーザー 草苺奶昔
提出日時 2023-03-13 19:39:27
言語 PyPy3
(7.3.15)
結果
AC  
実行時間 497 ms / 2,000 ms
コード長 2,802 bytes
コンパイル時間 231 ms
コンパイル使用メモリ 82,344 KB
実行使用メモリ 178,816 KB
最終ジャッジ日時 2024-09-18 07:41:04
合計ジャッジ時間 11,159 ms
ジャッジサーバーID
（参考情報） 		judge1 / judge5
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ファイルパターン 結果
sample AC * 3
other AC * 41
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 # 

import sys


sys.setrecursionlimit(int(1e9))

from typing import Callable, Generic, List, TypeVar

T = TypeVar("T")


class Rerooting(Generic[T]):

    __slots__ = ("adjList", "_n", "_decrement")

    def __init__(self, n: int, decrement: int = 0):
        self.adjList = [[] for _ in range(n)]
        self._n = n
        self._decrement = decrement

    def addEdge(self, u: int, v: int) -> None:
        u -= self._decrement
        v -= self._decrement
        self.adjList[u].append(v)
        self.adjList[v].append(u)

    def rerooting(
        self,
        e: Callable[[int], T],
        op: Callable[[T, T], T],
        composition: Callable[[T, int, int, int], T],
        root=0,
    ) -> List["T"]:
        root -= self._decrement
        assert 0 <= root < self._n
        parents = [-1] * self._n
        order = [root]
        stack = [root]
        while stack:
            cur = stack.pop()
            for next in self.adjList[cur]:
                if next == parents[cur]:
                    continue
                parents[next] = cur
                order.append(next)
                stack.append(next)

        dp1 = [e(i) for i in range(self._n)]
        dp2 = [e(i) for i in range(self._n)]
        for cur in order[::-1]:
            res = e(cur)
            for next in self.adjList[cur]:
                if parents[cur] == next:
                    continue
                dp2[next] = res
                res = op(res, composition(dp1[next], cur, next, 0))
            res = e(cur)
            for next in self.adjList[cur][::-1]:
                if parents[cur] == next:
                    continue
                dp2[next] = op(res, dp2[next])
                res = op(res, composition(dp1[next], cur, next, 0))
            dp1[cur] = res

        for newRoot in order[1:]:
            parent = parents[newRoot]
            dp2[newRoot] = composition(op(dp2[newRoot], dp2[parent]), parent, newRoot, 1)
            dp1[newRoot] = op(dp1[newRoot], dp2[newRoot])
        return dp1


def e(root: int) -> int:
    return 0

def op(childRes1: int, childRes2: int) -> int:
    return childRes1 + childRes2

def composition(fromRes: int, parent: int, cur: int, direction: int) -> int:
    if direction == 0:  # cur -> parent
        return fromRes + subSize[cur]
    return fromRes + (n - subSize[cur])  # parent -> cur

def dfsForSubSize(cur: int, parent: int) -> int:
    res = 1
    for next in R.adjList[cur]:
        if next != parent:
            res += dfsForSubSize(next, cur)
    subSize[cur] = res
    return res

n = int(input())
R = Rerooting(n)
for _ in range(n - 1):
    u, v = map(int, input().split())
    R.addEdge(u - 1, v - 1)

subSize = [0] * n
dfsForSubSize(0, -1)
dp = R.rerooting(e=e, op=op, composition=composition, root=0)
print(sum(dp) + n * n)
0