/*
* @(#)MathUtil.java 1.0 Apr 26, 2008
*
* The MIT License
*
* Copyright (c) 2008 Malachi de AElfweald
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
import java.math.BigDecimal;
import java.math.BigInteger;
import java.math.RoundingMode;
public class Util{
protected static BigInteger BigIntegerZERO = BigInteger.ZERO;
protected static BigInteger BigIntegerONE = BigInteger.ONE;
protected static BigInteger BigIntegerTWO = BigInteger.valueOf(2);
protected static BigInteger BigIntegerTHREE=BigInteger.valueOf(3);
protected static BigInteger FactorialBreakpoint = BigInteger.valueOf(96);
protected static BigDecimal BigDecimalZERO = BigDecimal.ZERO;
protected static BigDecimal BigDecimalONE = BigDecimal.ONE;
protected static BigDecimal BigDecimalTWO = new BigDecimal(2);
protected static BigDecimal BigDecimalFOUR = new BigDecimal(4);
public static BigInteger bitwiseGcd(BigInteger u, BigInteger v)
{
if(u.equals(BigInteger.ZERO)) return v;
if(v.equals(BigInteger.ZERO)) return u;
// System.out.format("u=%s=%s\nu.getLowestSetBit()=%s\n%s>>%s=%s = %s\n", u, u.toString(2), u.getLowestSetBit(), u, u.getLowestSetBit(), u.shiftRight(u.getLowestSetBit()), u.shiftRight(u.getLowestSetBit()).toString(2));
int uBit = u.getLowestSetBit();
int vBit = v.getLowestSetBit();
int k = (uBit <= vBit ? uBit : vBit);
while(u.signum() > 0)
{
// first ensure that both are odd
u = u.shiftRight(u.getLowestSetBit());
v = v.shiftRight(v.getLowestSetBit());
if(u.subtract(v).signum() >= 0)
{
u = (u.subtract(v)).shiftRight(1);
}else{
v = (v.subtract(u)).shiftRight(1);
}
}
return v.shiftLeft(k);
}
}