Java:获取最大公约数，哪种方法更好？

Question

从这个问题Java: get greatest common divisor

在获取任何数据类型的gcd时无论是int, long, Integer, Long, which answer在精度、速度、CPU 使用率等方面更好？

答:

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

乙:

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

Answer 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));

打印:

GCD:13

gcdThing:124