def extended_gcd(a, b):
    # r = gcd(a,b) i = multiplicitive inverse of a mod b
    #      or      j = multiplicitive inverse of b mod a
    # Neg return values for i or j are made positive mod b or a respectively
    # Iterateive Version is faster and uses much less stack space
    x = 0
    y = 1
    lx = 1
    ly = 0
    oa = a                             #Remember original a/b to remove 
    ob = b                             #negative values from return results
    while b != 0:
        q = a // b
        (a, b)  = (b, a % b)
        (x, lx) = ((lx - (q * x)),x)
        (y, ly) = ((ly - (q * y)),y)
    if (lx < 0): lx += ob              #If neg wrap modulo orignal b
    if (ly < 0): ly += oa              #If neg wrap modulo orignal a
    return (a, lx, ly)                 #Return only positive values
Returns a tuple (r, i, j) such that r = gcd(a, b) = ia + jb
dataset/ETHPy150Open CouchPotato/CouchPotatoServer/libs/rsa/common.py/extended_gcd