This class supports conversions between the following units: + *
This class is final and cannot be instantiated. + * + * @author krishna-medapati (https://github.com/krishna-medapati) + * @see Wikipedia: Temperature Conversion + */ +public final class TemperatureConverter { + + private TemperatureConverter() { + } + + public static double celsiusToFahrenheit(double celsius) { + return celsius * 9.0 / 5.0 + 32.0; + } + + public static double celsiusToKelvin(double celsius) { + return celsius + 273.15; + } + + public static double fahrenheitToCelsius(double fahrenheit) { + return (fahrenheit - 32.0) * 5.0 / 9.0; + } + + public static double fahrenheitToKelvin(double fahrenheit) { + return (fahrenheit - 32.0) * 5.0 / 9.0 + 273.15; + } + + public static double kelvinToCelsius(double kelvin) { + return kelvin - 273.15; + } + + public static double kelvinToFahrenheit(double kelvin) { + return (kelvin - 273.15) * 9.0 / 5.0 + 32.0; + } +} diff --git a/src/main/java/com/thealgorithms/maths/SmithNumber.java b/src/main/java/com/thealgorithms/maths/SmithNumber.java new file mode 100644 index 000000000000..c06e0023d9bb --- /dev/null +++ b/src/main/java/com/thealgorithms/maths/SmithNumber.java @@ -0,0 +1,52 @@ +package com.thealgorithms.maths; + +import com.thealgorithms.maths.Prime.PrimeCheck; + +/** + * In number theory, a smith number is a composite number for which, in a given number base, + * the sum of its digits is equal to the sum of the digits in its prime factorization in the same base. + * + * For example, in base 10, 378 = 21 X 33 X 71 is a Smith number since 3 + 7 + 8 = 2 X 1 + 3 X 3 + 7 X 1, + * and 22 = 21 X 111 is a Smith number, because 2 + 2 = 2 X 1 + (1 + 1) X 1. + * + * Wiki: https://en.wikipedia.org/wiki/Smith_number + */ +public final class SmithNumber { + + private SmithNumber() { + } + + private static int primeFactorDigitSum(int n) { + int sum = 0; + int num = n; + + // Factorize the number using trial division + for (int i = 2; i * i <= num; i++) { + while (n % i == 0) { // while i divides n + sum += SumOfDigits.sumOfDigits(i); // add sum of digits of factor + n /= i; // divide n by the factor + } + } + + // If n is still > 1, it itself is a prime factor + if (n > 1) { + sum += SumOfDigits.sumOfDigits(n); + } + + return sum; + } + + /** + * Check if {@code number} is Smith number or not + * + * @param number the number + * @return {@code true} if {@code number} is a Smith number, otherwise false + */ + public static boolean isSmithNumber(int number) { + if (PrimeCheck.isPrime(number)) { + return false; // Smith numbers must be composite + } + + return SumOfDigits.sumOfDigits(number) == primeFactorDigitSum(number); + } +} diff --git a/src/test/java/com/thealgorithms/conversions/TemperatureConverterTest.java b/src/test/java/com/thealgorithms/conversions/TemperatureConverterTest.java new file mode 100644 index 000000000000..24d55b706f36 --- /dev/null +++ b/src/test/java/com/thealgorithms/conversions/TemperatureConverterTest.java @@ -0,0 +1,54 @@ +package com.thealgorithms.conversions; + +import static org.junit.jupiter.api.Assertions.assertEquals; + +import org.junit.jupiter.api.Test; + +class TemperatureConverterTest { + + private static final double DELTA = 0.01; + + @Test + void testCelsiusToFahrenheit() { + assertEquals(32.0, TemperatureConverter.celsiusToFahrenheit(0.0), DELTA); + assertEquals(212.0, TemperatureConverter.celsiusToFahrenheit(100.0), DELTA); + assertEquals(-40.0, TemperatureConverter.celsiusToFahrenheit(-40.0), DELTA); + assertEquals(98.6, TemperatureConverter.celsiusToFahrenheit(37.0), DELTA); + } + + @Test + void testCelsiusToKelvin() { + assertEquals(273.15, TemperatureConverter.celsiusToKelvin(0.0), DELTA); + assertEquals(373.15, TemperatureConverter.celsiusToKelvin(100.0), DELTA); + assertEquals(233.15, TemperatureConverter.celsiusToKelvin(-40.0), DELTA); + } + + @Test + void testFahrenheitToCelsius() { + assertEquals(0.0, TemperatureConverter.fahrenheitToCelsius(32.0), DELTA); + assertEquals(100.0, TemperatureConverter.fahrenheitToCelsius(212.0), DELTA); + assertEquals(-40.0, TemperatureConverter.fahrenheitToCelsius(-40.0), DELTA); + assertEquals(37.0, TemperatureConverter.fahrenheitToCelsius(98.6), DELTA); + } + + @Test + void testFahrenheitToKelvin() { + assertEquals(273.15, TemperatureConverter.fahrenheitToKelvin(32.0), DELTA); + assertEquals(373.15, TemperatureConverter.fahrenheitToKelvin(212.0), DELTA); + assertEquals(233.15, TemperatureConverter.fahrenheitToKelvin(-40.0), DELTA); + } + + @Test + void testKelvinToCelsius() { + assertEquals(0.0, TemperatureConverter.kelvinToCelsius(273.15), DELTA); + assertEquals(100.0, TemperatureConverter.kelvinToCelsius(373.15), DELTA); + assertEquals(-273.15, TemperatureConverter.kelvinToCelsius(0.0), DELTA); + } + + @Test + void testKelvinToFahrenheit() { + assertEquals(32.0, TemperatureConverter.kelvinToFahrenheit(273.15), DELTA); + assertEquals(212.0, TemperatureConverter.kelvinToFahrenheit(373.15), DELTA); + assertEquals(-40.0, TemperatureConverter.kelvinToFahrenheit(233.15), DELTA); + } +} diff --git a/src/test/java/com/thealgorithms/maths/SmithNumberTest.java b/src/test/java/com/thealgorithms/maths/SmithNumberTest.java new file mode 100644 index 000000000000..4e2ba0b88e33 --- /dev/null +++ b/src/test/java/com/thealgorithms/maths/SmithNumberTest.java @@ -0,0 +1,22 @@ +package com.thealgorithms.maths; + +import static org.junit.jupiter.api.Assertions.assertFalse; +import static org.junit.jupiter.api.Assertions.assertTrue; + +import org.junit.jupiter.params.ParameterizedTest; +import org.junit.jupiter.params.provider.CsvSource; + +class SmithNumberTest { + + @ParameterizedTest + @CsvSource({"4", "22", "121", "562", "985", "4937775"}) + void positiveSmithNumbersTest(int n) { + assertTrue(SmithNumber.isSmithNumber(n)); + } + + @ParameterizedTest + @CsvSource({"2", "11", "100", "550", "999", "1234557"}) + void negativeSmithNumbersTest(int n) { + assertFalse(SmithNumber.isSmithNumber(n)); + } +}