Here you can find the source of gcd(Integer... values)
| Parameter | Description |
|---|---|
| values | values for which the gcd is to be computed |
public static int gcd(Integer... values)
//package com.java2s; /*//from w ww.j a va2s . c o m * ============================================================================= * Simplified BSD License, see http://www.opensource.org/licenses/ * ----------------------------------------------------------------------------- * Copyright (c) 2008-2009, Marco Terzer, Zurich, Switzerland * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions are met: * * * Redistributions of source code must retain the above copyright notice, * this list of conditions and the following disclaimer. * * Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * Neither the name of the Swiss Federal Institute of Technology Zurich * nor the names of its contributors may be used to endorse or promote * products derived from this software without specific prior written * permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE * POSSIBILITY OF SUCH DAMAGE. * ============================================================================= */ public class Main { /** * Calculates the greatest common divisor of the specified integer numbers. * This method might be useful to scale down a vector of integer numbers. * <p> * If all numbers are negative, the resulting gcd is also negative. If all * numbers are zero, the result is zero. Otherwise, the result is positive. * * @param values values for which the gcd is to be computed * @return gcd of all values, negative if all values negative, zero * if all values zero, positive otherwise */ public static int gcd(Integer... values) { if (values.length == 0) return 1; int allSgn = signum(values[0].intValue()); int gcd = values[0].intValue(); for (int i = 1; i < values.length; i++) { if (allSgn != signum(values[i].intValue())) allSgn = 1; if (gcd == 0 || gcd == 1) break; gcd = gcd(gcd, values[i].intValue()); } return allSgn == 0 ? 0 : allSgn * gcd; } /** * Calculates the greatest common divisor of the specified integer numbers. * This method might be useful to scale down a vector of integer numbers. * <p> * If all numbers are negative, the resulting gcd is also negative. If all * numbers are zero, the result is zero. Otherwise, the result is positive. * * @param values values for which the gcd is to be computed * @return gcd of all values, negative if all values negative, zero * if all values zero, positive otherwise */ public static int gcd(int... values) { if (values.length == 0) return 1; int allSgn = signum(values[0]); int gcd = values[0]; for (int i = 1; i < values.length; i++) { if (allSgn != signum(values[i])) allSgn = 1; if (gcd == 0 || gcd == 1) break; gcd = gcd(gcd, values[i]); } return allSgn == 0 ? 0 : allSgn * gcd; } /** * Calculates the greatest common divisor of the specified long numbers. * This method might be useful to scale down a vector of long numbers. * <p> * If all numbers are negative, the resulting gcd is also negative. If all * numbers are zero, the result is zero. Otherwise, the result is positive. * * @param values values for which the gcd is to be computed * @return gcd of all values, negative if all values negative, zero * if all values zero, positive otherwise */ public static long gcd(Long... values) { if (values.length == 0) return 1; int allSgn = signum(values[0].longValue()); long gcd = values[0].longValue(); for (int i = 1; i < values.length; i++) { if (allSgn != signum(values[i].longValue())) allSgn = 1; if (gcd == 0 || gcd == 1) break; gcd = gcd(gcd, values[i].longValue()); } return allSgn == 0 ? 0 : allSgn * gcd; } /** * Calculates the greatest common divisor of the specified long numbers. * This method might be useful to scale down a vector of long numbers. * <p> * If all numbers are negative, the resulting gcd is also negative. If all * numbers are zero, the result is zero. Otherwise, the result is positive. * * @param values values for which the gcd is to be computed * @return gcd of all values, negative if all values negative, zero * if all values zero, positive otherwise */ public static long gcd(long... values) { if (values.length == 0) return 1; int allSgn = signum(values[0]); long gcd = values[0]; for (int i = 1; i < values.length; i++) { if (allSgn != signum(values[i])) allSgn = 1; if (gcd == 0 || gcd == 1) break; gcd = gcd(gcd, values[i]); } return allSgn == 0 ? 0 : allSgn * gcd; } /** * Returns the greatest common divisor of iA and iB using standard euclidian * algorithm */ public static int gcd(int iA, int iB) { iA = Math.abs(iA); iB = Math.abs(iB); if (iA == 0) return iB; if (iB == 0) return iA; if (iA < 0 || iB < 0) { //at least one must be MIN_VALUE, which is a even number if (0 != ((iA | iB) & 0x1)) { //the other number is not even --> GCD=1 return 1; } //both are even numbers, divide by 2 iA = Math.abs(iA >>> 1); iB = Math.abs(iB >>> 1); } int iMax = Math.max(iA, iB); int iMin = Math.min(iA, iB); while (iMax != iMin) { if (iMax % iMin == 0) return iMin; int tmp = iMin; iMin = iMax - (iMax / iMin) * iMin; iMax = tmp; } return iMin; } /** * Returns the greatest common divisor of iA and iB using standard euclidian * algorithm */ public static long gcd(long iA, long iB) { iA = Math.abs(iA); iB = Math.abs(iB); if (iA == 0) return iB; if (iB == 0) return iA; if (iA < 0 || iB < 0) { //at least one must be MIN_VALUE, which is a even number if (0 != ((iA | iB) & 0x1)) { //the other number is not even --> GCD=1 return 1; } //both are even numbers, divide by 2 iA = Math.abs(iA >>> 1); iB = Math.abs(iB >>> 1); } long iMax = Math.max(iA, iB); long iMin = Math.min(iA, iB); while (iMax != iMin) { if (iMax % iMin == 0) return iMin; long tmp = iMin; iMin = iMax - (iMax / iMin) * iMin; iMax = tmp; } return iMin; } /** * Returns the signum of the long value, i.e. 1/-1/0 for a positive, * negative or zero value * * @see Math#signum(double) */ public static int signum(long value) { return value == 0 ? 0 : value > 0 ? 1 : -1; } /** * Returns the signum of the int value, i.e. 1/-1/0 for a positive, * negative or zero value * * @see Math#signum(double) */ public static int signum(int value) { return value == 0 ? 0 : value > 0 ? 1 : -1; } }