結果

問題 No.1753 Don't cheat.
コンテスト
ユーザー zkou
提出日時 2021-06-19 17:24:00
言語 PyPy3
(7.3.15)
結果
AC  
実行時間 1,187 ms / 3,000 ms
コード長 2,742 bytes
コンパイル時間 386 ms
コンパイル使用メモリ 82,452 KB
実行使用メモリ 86,408 KB
最終ジャッジ日時 2024-12-31 18:25:25
合計ジャッジ時間 27,014 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 * 2
other AC * 30
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 # 

MOD = 998244353
half = pow(2, MOD - 2, MOD)


def int2frac(n, m=None, N = 10000, D = 10000):
    """
    Return (r, s) s.t. r = s * n (mod m) if such a pair exists.
    Otherwise, return (0, 0).

    Parameters
    ----------
    n: an integer that will be represented as a fraction.   
    m: A modulus used to represent n.     
    N: An upperbound of r, which is the numerator of n. 
    D: An upperbound of s, which is the denominator of n.    
    """
    def gcd(a, b):
        while b:
            a, b = b, a % b
        return a
    if m is None:
        m = MOD
    v = (m, 0)
    w = (n, 1)
    while w[0] > N:
        q = v[0] // w[0]
        v, w = w, (v[0] - q * w[0], v[1] - q * w[1])
    if w[1] < 0:
        w = (-w[0], -w[1])
    if w[1] <= D and gcd(w[0], w[1]) == 1:
        return w
    else:
        return (0, 0)


def fwht(a) -> None:
    """
    In-place Fast Walsh–Hadamard Transform of array a.
    Reference: https://en.wikipedia.org/wiki/Fast_Walsh%E2%80%93Hadamard_transform
    """
    h = 1
    while h < len(a):
        for i in range(0, len(a), h * 2):
            for j in range(i, i + h):
                x = a[j]
                y = a[j + h]
                a[j] = (x + y) % MOD
                a[j + h] = (x - y) % MOD
        h *= 2

def ifwht(a) -> None:
    """
    In-place Inverse Fast Walsh–Hadamard Transform of array a.
    Reference: https://en.wikipedia.org/wiki/Fast_Walsh%E2%80%93Hadamard_transform
    """
    h = 1
    while h < len(a):
        for i in range(0, len(a), h * 2):
            for j in range(i, i + h):
                x = a[j]
                y = a[j + h]
                a[j] = (x + y) * half % MOD
                a[j + h] = (x - y) * half % MOD
        h *= 2

N = int(input())
As = list(map(int, input().split()))

# assert 1 <= N <= 2 * 10 ** 3
# assert all(0 <= A <= 10 ** 5 for A in As)
# assert N + 1 == len(As)
# assert As[0]

sumAs = sum(As)
invsumAs = pow(sum(As), MOD - 2, MOD)
for i in range(N + 1):
    As[i] *= invsumAs
    As[i] %= MOD

# print([int2frac(A) for A in As])

z = 1 << N.bit_length()

e0 = [0] * z
e0[0] = 1
fwht(e0)

As_fwht = As + [0] * (z - N - 1)
fwht(As_fwht)

fwhts = []
for i, A in enumerate(As):
    t = [0] * z
    t[i] = A
    fwht(t)
    fwhts.append(t)

q = [pow(1 - As_fwht[k] + fwhts[0][k], MOD - 2, MOD) * As[0] % MOD * e0[k] % MOD for k in range(z)]
ifwht(q)

psum = [0] * z
for x in range(1, N + 1):
    p = [pow(1 - As_fwht[k] + fwhts[x][k] + fwhts[0][k], MOD - 2, MOD) * As[x] % MOD * e0[k] % MOD for k in range(z)]
    ifwht(p)
    for i, e in enumerate(p):
        psum[i] += e
        psum[i] %= MOD

answer = q[0]
for xor in range(z):
    answer += psum[xor] * q[xor] % MOD
    answer %= MOD

print((1 - answer) % MOD)
0