RosettaCodeData/Task/Pells-equation/Python/pells-equation.py

23 lines
496 B
Python

import math
def solvePell(n):
x = int(math.sqrt(n))
y, z, r = x, 1, x << 1
e1, e2 = 1, 0
f1, f2 = 0, 1
while True:
y = r * z - y
z = (n - y * y) // z
r = (x + y) // z
e1, e2 = e2, e1 + e2 * r
f1, f2 = f2, f1 + f2 * r
a, b = f2 * x + e2, f2
if a * a - n * b * b == 1:
return a, b
for n in [61, 109, 181, 277]:
x, y = solvePell(n)
print("x^2 - %3d * y^2 = 1 for x = %27d and y = %25d" % (n, x, y))