求最大公约数（Java）

/**
 * 求最大公约数
 * */
public class GetGCD {
    public static int gcd(int a, int b) {
        if(a == b) {
            return a;
        }

        if ((a & 1) == 0 && (b & 1) == 0){
            return gcd(a >> 1, b >> 1) << 1;
        }
        else if((a & 1) == 0 && (b & 1) != 0){
            return gcd(a >> 1, b);
        }
        else if ((a & 1) != 0 && (b & 1) == 0){
            return gcd(a , b >> 1);
        }
        else {
            int big = a > b ? a : b;
            int small = a < b ? a : b;
            return gcd(big-small, small);
        }
    }

    public static void main(String [] args) {
        System.out.println(gcd(4,8));
    }
}