Calculate greatest common divisor and least common multiple using the Stein algorithm

The Stein algorithm, which is efficient for calculating gcd and LCM, is used to calculate large numbers:

function gcd (b) {if (a = = b) {return A;} var bigger;var smaller;if (a>b) {bigger = A;smaller = b;} Else{bigger = B;smaller = A;} if (smaller = = 0) {return bigger;} if (bigger%2 = = 0 && smaller% 2 = 0) {return 2*gcd (BIGGER/2,SMALLER/2);} else if (bigger%2 = = 0) {return gcd (Bigger/2,smaller);} else if (smaller%2 = = 0) {return gcd (BIGGER,SMALLER/2);} Else{return gcd ((Bigger+smaller)/2, (Bigger-smaller)/2);}} function LCM (A, b) {return A*B/GCD (A, b);}

Calculate greatest common divisor and least common multiple using the Stein algorithm