org.monte.media.math.IntMath Maven / Gradle / Ivy

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package org.monte.media.math;

import java.math.BigInteger;


public class IntMath {


    public IntMath() {
    }


    public static int gcd(int a, int b) {





        a = Math.abs(a);
        b = Math.abs(b);

        while (a > 0 && b > 0) {
            a = a % b;
            if (a > 0) b = b % a;
        }
        return a + b;
    }

    public static long gcd(long a, long b) {





        a = Math.abs(a);
        b = Math.abs(b);

        while (a > 0 && b > 0) {
            a = a % b;
            if (a > 0) b = b % a;
        }
        return a + b;
    }

    public static BigInteger gcd(BigInteger a, BigInteger b) {





        a = a.abs();
        b = b.abs();

        while (a.compareTo(BigInteger.ZERO) > 0 && b.compareTo(BigInteger.ZERO) > 0) {
            a = a.mod(b);
            if (a.compareTo(BigInteger.ZERO) > 0) b = b.mod(a);
        }
        return a.add(b);
    }


    public static int scm(int a, int b) {





        if (a == 0 || b == 0) return 0;

        a = Math.abs(a);
        b = Math.abs(b);

        int u = a;
        int v = b;

        while (a != b) {
            if (a < b) {
                b -= a;
                v += u;
            } else {
                a -= b;
                u += v;
            }
        }



        return (u + v) / 2;
    }

    public static long scm(long a, long b) {





        if (a == 0 || b == 0) return 0;

        a = Math.abs(a);
        b = Math.abs(b);
        if (b==1)return a;
        if (a==1)return b;

        long u = a;
        long v = b;


        while (a != b) {
            if (a < b) {
                b -= a;
                v += u;
            } else {
                a -= b;
                u += v;
            }
        }



        return (u + v) / 2;
    }

    public static BigInteger scm(BigInteger a, BigInteger b) {





        if (a.compareTo(BigInteger.ZERO) == 0 || b.compareTo(BigInteger.ZERO) == 0) {
            return BigInteger.ZERO;
        }

        a = a.abs();
        b = b.abs();
        if (b.compareTo(BigInteger.ONE)==0)return a;
        if (a.compareTo(BigInteger.ONE)==0)return b;

        BigInteger u = a;
        BigInteger v = b;


        while (a.compareTo(b) != 0) {
            if (a .compareTo( b)<0) {
                b = b.subtract(a);
                v = v.add(u);
            } else {
                a = a.subtract(b);
                u = u.add(v);
            }
        }



        return (u.add(v)).divide(BigInteger.valueOf(2));
    }


    public static int reverseBits(int a) {
        return reverseBits(a, 32);
    }

    public static int reverseBits(int a, int numBits) {
        int b = 0;
        for (int i=0; i < numBits; i++) {
            b <<= 1;
            b |= (a & 1);
            a >>>= 1;
        }
        return b;

    }

    public static void main(String[] args) {
        for (int i=0; i < 8; i++) {
            int a = 1<