Data commit

Task/Arithmetic-derivative/Java/arithmetic-derivative.java

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+import java.math.BigInteger;
+
+public final class ArithmeticDerivative {
+
+	public static void main(String[] aArgs) {
+        System.out.println("Arithmetic derivatives for -99 to 100 inclusive:");
+		for ( int n = -99, column = 0; n <= 100; n++ ) {
+			System.out.print(String.format("%4d%s",
+				derivative(BigInteger.valueOf(n)), ( ++column % 10 == 0 ) ? "\n" : " "));
+		}
+		System.out.println();
+		
+		final BigInteger seven = BigInteger.valueOf(7);
+		for ( int power = 1; power <= 20; power++ ) {
+			System.out.println(String.format("%s%2d%s%d",
+				"D(10^", power, ") / 7 = ", derivative(BigInteger.TEN.pow(power)).divide(seven)));
+		}
+	}
+	
+	private static BigInteger derivative(BigInteger aNumber) {
+		if ( aNumber.signum() == -1 ) {
+			return derivative(aNumber.negate()).negate();
+		}
+		if ( aNumber == BigInteger.ZERO || aNumber == BigInteger.ONE ) {
+			return BigInteger.ZERO;
+		}
+		BigInteger divisor = BigInteger.TWO;
+		while ( divisor.multiply(divisor).compareTo(aNumber) <= 0 ) {
+		    if ( aNumber.mod(divisor).signum() == 0 ) {
+		        final BigInteger quotient = aNumber.divide(divisor);
+		        return quotient.multiply(derivative(divisor)).add(divisor.multiply(derivative(quotient)));
+		    }
+		    divisor = divisor.add(BigInteger.ONE);
+		}
+		return BigInteger.ONE;
+	}
+
+}