Java BigInteger.gcd方法代码示例

import java.math.BigInteger; //导入方法依赖的package包/类
/**
 * This method is the core of all constructors. It takes the numerator and
 * the  denominator as BigIntegers and produces a BigRational, reducing the
 * fraction if needed.
 *
 * @param numerator The numerator of the rational number
 * @param denominator The denominator of the rational number
 * @param isNormal True if the fraction is already in reduced form, false otherwise.
 */
private void init(BigInteger numerator, BigInteger denominator, boolean isNormal) {
    // If isNormal, then we do not need to reduce the fraction and compute the gcd
    // deal with x / 0
    if (denominator.equals(BigInteger.ZERO)) {
        throw new RuntimeException("Denominator is zero");
    }

    if (!isNormal) {
        // reduce fraction
        BigInteger g = numerator.gcd(denominator);

        num = numerator.divide(g);
        den = denominator.divide(g);
    } else {
        num = numerator;
        den = denominator;
    }
}
 

import java.math.BigInteger; //导入方法依赖的package包/类
/**
    * Creates a new Fraction of the form (numerator/denominator) and divides both
    * of them by their common greatest divisor to keep the numbers as short as
    * possible.
    * @param numerator the numerator of the fraction
    * @param denominator the denominator of the fraction
    */
   public Fraction(BigInteger numerator, BigInteger denominator){
if (numerator.equals(BigInteger.ZERO)){
    this.numerator = BigInteger.ZERO;
    this.denominator = BigInteger.ONE;
} else {
    BigInteger gcd = numerator.gcd(denominator);
    if (gcd.equals(BigInteger.ONE)){
	this.numerator = numerator;
	this.denominator = denominator;
    } else {
	this.numerator = numerator.divide(gcd);
	this.denominator = denominator.divide(gcd);
    }
    if (this.denominator.signum() == -1){
	this.numerator = this.numerator.negate();
	this.denominator = this.denominator.negate();
    }
}
int shift = this.denominator.bitLength() - maxBitLength;
if (shift > 0){
    this.denominator = this.denominator.shiftRight(shift);
    this.numerator = this.numerator.shiftRight(shift);
}
   }
 

import java.math.BigInteger; //导入方法依赖的package包/类
/**
 * Computation of the least common multiple of a set of BigIntegers.
 *
 * @param numbers - the set of numbers
 * @return the lcm(numbers)
 */
public static BigInteger leastCommonMultiple(BigInteger[] numbers)
{
    int n = numbers.length;
    BigInteger result = numbers[0];
    for (int i = 1; i < n; i++)
    {
        BigInteger gcd = result.gcd(numbers[i]);
        result = result.multiply(numbers[i]).divide(gcd);
    }
    return result;
}
 

import java.math.BigInteger; //导入方法依赖的package包/类
private long lcm(final long m, final long n) {
	if (m  == 0 && n == 0) {
		return 0;
	}
	final BigInteger mi = BigInteger.valueOf(m);
	final BigInteger ni = BigInteger.valueOf(n);
	final BigInteger gcd = mi.gcd(ni);
	final BigInteger r = mi.multiply(ni).divide(gcd);
	return r.longValue();
}
 

import java.math.BigInteger; //导入方法依赖的package包/类
/** The lowest common multiple
* @param a The first argument
* @param b The second argument
* @return lcm(|a|,|b|)
* @since 2010-08-27
* @author Richard J. Mathar
*/
static public BigInteger lcm(final BigInteger a, final BigInteger b)
{
        BigInteger g = a.gcd(b) ;
        return a.multiply(b).abs().divide(g) ;
}