diff --git a/src/main/java/com/thealgorithms/greedyalgorithms/DigitSeparation.java b/src/main/java/com/thealgorithms/greedyalgorithms/DigitSeparation.java new file mode 100644 index 000000000000..bee5f98cd2ee --- /dev/null +++ b/src/main/java/com/thealgorithms/greedyalgorithms/DigitSeparation.java @@ -0,0 +1,40 @@ +package com.thealgorithms.greedyalgorithms; + +import java.util.ArrayList; +import java.util.Collections; +import java.util.List; + +/** + * This class provides methods to separate the digits of a large positive number into a list. + */ +public class DigitSeparation { + public DigitSeparation() { + } + /** + * Separates the digits of a large positive number into a list in reverse order. + * @param largeNumber The large number to separate digits from. + * @return A list of digits in reverse order. + */ + public List digitSeparationReverseOrder(long largeNumber) { + List result = new ArrayList<>(); + if (largeNumber != 0) { + while (largeNumber != 0) { + result.add(Math.abs(largeNumber % 10)); + largeNumber = largeNumber / 10; + } + } else { + result.add(0L); + } + return result; + } + /** + * Separates the digits of a large positive number into a list in forward order. + * @param largeNumber The large number to separate digits from. + * @return A list of digits in forward order. + */ + public List digitSeparationForwardOrder(long largeNumber) { + List result = this.digitSeparationReverseOrder(largeNumber); + Collections.reverse(result); + return result; + } +} diff --git a/src/test/java/com/thealgorithms/greedyalgorithms/DigitSeparationTest.java b/src/test/java/com/thealgorithms/greedyalgorithms/DigitSeparationTest.java new file mode 100644 index 000000000000..1fe018ecce18 --- /dev/null +++ b/src/test/java/com/thealgorithms/greedyalgorithms/DigitSeparationTest.java @@ -0,0 +1,78 @@ +package com.thealgorithms.greedyalgorithms; + +import static org.junit.jupiter.api.Assertions.assertEquals; + +import java.util.List; +import org.junit.jupiter.api.Test; +public class DigitSeparationTest { + + @Test + public void testDigitSeparationReverseOrderSingleDigit() { + DigitSeparation digitSeparation = new DigitSeparation(); + List result = digitSeparation.digitSeparationReverseOrder(5); + assertEquals(List.of(5L), result); + } + + @Test + public void testDigitSeparationReverseOrderMultipleDigits() { + DigitSeparation digitSeparation = new DigitSeparation(); + List result = digitSeparation.digitSeparationReverseOrder(123); + assertEquals(List.of(3L, 2L, 1L), result); + } + + @Test + public void testDigitSeparationReverseOrderLargeNumber() { + DigitSeparation digitSeparation = new DigitSeparation(); + List result = digitSeparation.digitSeparationReverseOrder(123456789); + assertEquals(List.of(9L, 8L, 7L, 6L, 5L, 4L, 3L, 2L, 1L), result); + } + + @Test + public void testDigitSeparationReverseOrderZero() { + DigitSeparation digitSeparation = new DigitSeparation(); + List result = digitSeparation.digitSeparationReverseOrder(0); + assertEquals(List.of(0L), result); + } + + @Test + public void testDigitSeparationReverseOrderNegativeNumbers() { + DigitSeparation digitSeparation = new DigitSeparation(); + List result = digitSeparation.digitSeparationReverseOrder(-123); + assertEquals(List.of(3L, 2L, 1L), result); + } + + @Test + public void testDigitSeparationForwardOrderSingleDigit() { + DigitSeparation digitSeparation = new DigitSeparation(); + List result = digitSeparation.digitSeparationForwardOrder(5); + assertEquals(List.of(5L), result); + } + + @Test + public void testDigitSeparationForwardOrderMultipleDigits() { + DigitSeparation digitSeparation = new DigitSeparation(); + List result = digitSeparation.digitSeparationForwardOrder(123); + assertEquals(List.of(1L, 2L, 3L), result); + } + + @Test + public void testDigitSeparationForwardOrderLargeNumber() { + DigitSeparation digitSeparation = new DigitSeparation(); + List result = digitSeparation.digitSeparationForwardOrder(123456789); + assertEquals(List.of(1L, 2L, 3L, 4L, 5L, 6L, 7L, 8L, 9L), result); + } + + @Test + public void testDigitSeparationForwardOrderZero() { + DigitSeparation digitSeparation = new DigitSeparation(); + List result = digitSeparation.digitSeparationForwardOrder(0); + assertEquals(List.of(0L), result); + } + + @Test + public void testDigitSeparationForwardOrderNegativeNumber() { + DigitSeparation digitSeparation = new DigitSeparation(); + List result = digitSeparation.digitSeparationForwardOrder(-123); + assertEquals(List.of(1L, 2L, 3L), result); + } +}