結果

問題 No.1857 Gacha Addiction
ユーザー MitarushiMitarushi
提出日時 2021-12-31 22:11:53
言語 PyPy3
(7.3.15)
結果
AC  
実行時間 5,059 ms / 6,000 ms
コード長 2,653 bytes
コンパイル時間 299 ms
コンパイル使用メモリ 81,792 KB
実行使用メモリ 262,492 KB
最終ジャッジ日時 2024-07-01 21:50:46
合計ジャッジ時間 152,342 ms
ジャッジサーバーID
(参考情報)
judge2 / judge3
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 * 4
other AC * 43
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 collections
mod = 998244353
def fft_inplace(a, w):
n = len(a)
m = n
t = 1
while m >= 2:
mh = m >> 1
for i in range(0, n, m):
for s in range(mh):
j, k = i+s, i+mh+s
a[j], a[k] = (a[j]+a[k]) % mod, (a[j]-a[k])*w[s*t] % mod
m = mh
t *= 2
def ifft_inplace(a, w):
n = len(a)
m = 2
t = -(n >> 1)
while m <= n:
mh = m >> 1
for i in range(0, n, m):
for s in range(mh):
j, k = i+s, i+mh+s
a[k] *= w[s*t]
a[j], a[k] = (a[j]+a[k]) % mod, (a[j]-a[k]) % mod
m <<= 1
t //= 2
n_inv = pow(n, mod-2, mod)
for i in range(n):
a[i] = a[i] * n_inv % mod
def normal_convolution(a, b):
n = max(len(a) + len(b) - 1, 1)
c = [0] * n
for i in range(len(a)):
for j in range(len(b)):
c[i+j] += a[i] * b[j]
for i in range(n):
c[i] %= mod
return c
def convolution(a, b):
n2 = max(len(a) + len(b), 1)
if len(a) * len(b) < 1 << 10:
return normal_convolution(a, b)
n = 1 << (n2-1).bit_length()
a = a + [0] * (n-len(a))
b = b + [0] * (n-len(b))
w_root = pow(3, (mod-1)//n, mod)
w = [1] * n
for i in range(1, n):
w[i] = w[i-1] * w_root % mod
fft_inplace(a, w)
fft_inplace(b, w)
c = [i*j % mod for i, j in zip(a, b)]
ifft_inplace(c, w)
return c[:n2]
class Poly:
def __init__(Self, coeffs):
Self.coeffs = coeffs
def __add__(Self, other):
n = max(len(Self.coeffs), len(other.coeffs))
result = [0] * n
for idx, i in enumerate(Self.coeffs):
result[idx] += i
for idx, i in enumerate(other.coeffs):
result[idx] += i
result[idx] %= mod
return Poly(result)
def __mul__(Self, other):
return Poly(convolution(Self.coeffs, other.coeffs))
class Fraction:
def __init__(Self, num, den):
Self.num = num
Self.den = den
def __add__(Self, other):
return Fraction(Self.num * other.den + Self.den * other.num, Self.den * other.den)
n, s = map(int, input().split())
s_inv = pow(s, mod-2, mod)
p = [i * s_inv % mod for i in map(int, input().split())]
fractions = collections.deque(
Fraction(Poly([0, i ** 2 % mod]), Poly([1, i])) for i in p
)
while len(fractions) > 1:
fractions.append(fractions.popleft() + fractions.popleft())
ans = 0
factorial = 2
for i in range(1, n + 1):
ans += fractions[0].num.coeffs[i] * factorial % mod
factorial = factorial * (i + 2) % mod
ans %= mod
print(ans)
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