Java: Get Greatest Common Divisor, which method is better?

问题

From this question Java: get greatest common divisor

In getting the gcd of any data type whether int, long, Integer, Long, which answer is better in terms of precision, speed, cpu usage, etc.?

A:

private static int gcdThing(int a, int b) {
    return BigInteger.valueOf(a).gcd(BigInteger.valueOf((b))).intValue();
}

B:

public int GCD(int a, int b) { return b==0 ? a : GCD(b, a%b); }

回答1:

    Random r = new Random();
    int[] ints = new int[500000];
    for (int i = 0 ; i < ints.length ; i++)
        ints[i] = r.nextInt();

    for (int i = 0 ; i < ints.length-1; i++)
        GCD(i,i+1);
    for (int i = 0 ; i < ints.length-1; i++)
        gcdThing(i, i + 1);

    long start = System.currentTimeMillis();
    for (int i = 0 ; i < ints.length-1; i++)
        GCD(i,i+1);
    System.out.println("GCD: " + (System.currentTimeMillis() - start));

    start = System.currentTimeMillis();
    for (int i = 0 ; i < ints.length-1; i++)
        gcdThing(i, i + 1);
    System.out.println("gcdThing: " + (System.currentTimeMillis() - start));

Prints:

GCD: 13

gcdThing: 124

来源：https://stackoverflow.com/questions/21570890/java-get-greatest-common-divisor-which-method-is-better