結果

問題 No.978 Fibonacci Convolution Easy
ユーザー mkawa2
提出日時 2020-01-31 22:32:11
言語 Python3
(3.13.1 + numpy 2.2.1 + scipy 1.14.1)
結果
AC  
実行時間 31 ms / 2,000 ms
コード長 2,786 bytes
コンパイル時間 232 ms
コンパイル使用メモリ 12,928 KB
実行使用メモリ 11,008 KB
最終ジャッジ日時 2024-09-18 21:00:03
合計ジャッジ時間 1,669 ms
ジャッジサーバーID
（参考情報） 		judge3 / judge2
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ファイルパターン 結果
other AC * 21
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(10 ** 6)
int1 = lambda x: int(x) - 1
p2D = lambda x: print(*x, sep="\n")
def II(): return int(sys.stdin.readline())
def MI(): return map(int, sys.stdin.readline().split())
def LI(): return list(map(int, sys.stdin.readline().split()))
def LLI(rows_number): return [LI() for _ in range(rows_number)]
def SI(): return sys.stdin.readline()[:-1]

class mint:
    def __init__(self, x):
        self.__x = x % md

    def __str__(self):
        return str(self.__x)

    def __add__(self, other):
        if isinstance(other, mint): other = other.__x
        return mint(self.__x + other)

    def __sub__(self, other):
        if isinstance(other, mint): other = other.__x
        return mint(self.__x - other)

    def __rsub__(self, other):
        return mint(other - self.__x)

    def __mul__(self, other):
        if isinstance(other, mint): other = other.__x
        return mint(self.__x * other)

    __radd__ = __add__
    __rmul__ = __mul__

    def __truediv__(self, other):
        if isinstance(other, mint): other = other.__x
        return mint(self.__x * pow(other, md - 2, md))

    def __pow__(self, power, modulo=None):
        return mint(pow(self.__x, power, md))

class Fibonacci:
    def __init__(self, p):
        coff = [1, p]
        self.f0 = [0, 1]
        # 上２つは問題ごとに手作業で設定
        # af(n)+bf(n+1)+cf(n+2)+df(n+3)=f(n+4)みたいなとき
        # coff=[a,b,c,d]
        # 初期値f0(f(0)からf(3))
        n = len(coff)
        ff = [[0] * n for _ in range(2 * n - 1)]
        for i in range(n): ff[i][i] = mint(1)
        for i in range(n, 2 * n - 1):
            ffi = ff[i]
            for j, c in enumerate(coff, i - n):
                ffj = ff[j]
                for k in range(n): ffi[k] += c * ffj[k]
        self.bn = 1 << (n - 1).bit_length()
        self.base = ff[self.bn]
        self.ff = ff
        self.n = n

    def __mm(self, aa, bb):
        n = self.n
        res = [0] * (n * 2 - 1)
        for i, a in enumerate(aa):
            for j, b in enumerate(bb):
                res[i + j] += a * b
        for i in range(n, 2 * n - 1):
            c = res[i]
            ffi = self.ff[i]
            for j in range(n):
                res[j] += c * ffi[j]
        return res[:n]

    def v(self, x):
        x-=1
        base = self.base
        aa = self.ff[x % self.bn]
        x //= self.bn
        while x:
            if x & 1: aa = self.__mm(aa, base)
            base = self.__mm(base, base)
            x >>= 1
        return sum(a * f for a, f in zip(aa, self.f0))

md = 10 ** 9 + 7
def main():
    def s(k):
        res=((1-p)*(f.v(k+1)-1)-p+f.v(k+2))/p
        return res

    n,p=MI()
    f=Fibonacci(p)
    ans=(s(n)**2+f.v(n)*f.v(n+1)/p)/2
    print(ans)

main()
0