結果

問題 No.1227 I hate ThREE
ユーザー mkawa2mkawa2
提出日時 2021-07-25 19:10:05
言語 PyPy3
(7.3.15)
結果
AC  
実行時間 385 ms / 2,000 ms
コード長 1,438 bytes
コンパイル時間 1,878 ms
コンパイル使用メモリ 81,664 KB
実行使用メモリ 122,880 KB
最終ジャッジ日時 2024-07-21 03:39:08
合計ジャッジ時間 10,023 ms
ジャッジサーバーID
(参考情報)
judge3 / judge5
このコードへのチャレンジ
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ファイルパターン 結果
sample AC * 3
other AC * 33
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 #
プレゼンテーションモードにする

import sys
# sys.setrecursionlimit(200005)
int1 = lambda x: int(x)-1
p2D = lambda x: print(*x, sep="\n")
def II(): return int(sys.stdin.readline())
def LI(): return list(map(int, sys.stdin.readline().split()))
def LI1(): return list(map(int1, sys.stdin.readline().split()))
def LLI(rows_number): return [LI() for _ in range(rows_number)]
def LLI1(rows_number): return [LI1() for _ in range(rows_number)]
def SI(): return sys.stdin.readline().rstrip()
# dij = [(0, 1), (-1, 0), (0, -1), (1, 0)]
dij = [(0, 1), (-1, 0), (0, -1), (1, 0), (1, 1), (1, -1), (-1, 1), (-1, -1)]
inf = 10**16
# md = 998244353
md = 10**9+7
n, c = LI()
to = [[] for _ in range(n)]
for _ in range(n-1):
u, v = LI1()
to[u].append(v)
to[v].append(u)
maxu = min(3*n-3, c)
maxj = min(6*n-6, c)
dp = [[1]*(maxj+1) for _ in range(n)]
dfsorder = []
parent = [-1]*n
stack = [0]
while stack:
u = stack.pop()
dfsorder.append(u)
for v in to[u]:
if v == parent[u]: continue
parent[v] = u
stack.append(v)
# print(dfsorder)
for u in dfsorder[::-1]:
for j in range(1, maxj+1):
for v in to[u]:
if v == parent[u]: continue
cur = 0
if j+3 <= maxj: cur += dp[v][j+3]
if j-3 > 0: cur += dp[v][j-3]
dp[u][j] = dp[u][j]*cur%md
ans = sum(dp[0][1:maxu+1])%md
suf = min(c-maxu, maxu)
ans += sum(dp[0][1:1+suf])
ans += (c-maxu-suf)*pow(2, n-1, md)%md
print(ans%md)
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