PY题解，网上的Chudnovsky算法

这是算法公式：
$\pi = \frac{426880 \sqrt{10005}}{ \sum\limits_{k=0}^{\infty} \frac{(6k)!}{(3k)!(k!)^3} \cdot \frac{13591409 + 545140134k}{(-640320^3)^k} }$
非常阴间公式，这使我的Ctrl键旋转

from decimal import Decimal, getcontext

def chudnovsky(precision):
    getcontext().prec = precision + 10
    C = Decimal(426880) * Decimal(10005).sqrt()
    M = Decimal(1)
    L = Decimal(13591409)
    X = Decimal(1)
    K = Decimal(6)
    S = L
    for k in range(1, precision // 14 + 10):
        M = M * (K**3 - 16*K) // (k**3)
        L = L + 545140134
        X = X * (-262537412640768000)
        term = M * L / X
        S += term
        K += 12
        if abs(term) < Decimal(10)**(-precision - 5):
            break
    pi = C / S
    return pi.quantize(Decimal(10)**(-precision))


if __name__ == "__main__":
    precision = int(input())
    pi_value = chudnovsky(precision+20)
    pi_str = str(pi_value)
    print(pi_str[:2])
    pr = pi_str[2:]
    for i in range(precision):
        print(pr[i], end="")
        if((i+1)%50==0):
            print(" ")
        elif((i+1)%10==0):
            print(" ", end="")