Merge branch 'master' into master

Author: varada610

DIRECTORY.md

@@ -12,7 +12,7 @@
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
         <maven.compiler.source>21</maven.compiler.source>
         <maven.compiler.target>21</maven.compiler.target>
-        <assertj.version>3.27.2</assertj.version>
+        <assertj.version>3.27.3</assertj.version>
     </properties>
 
     <dependencyManagement>

pom.xml

@@ -0,0 +1,100 @@
+package com.thealgorithms.conversions;
+
+import java.math.BigDecimal;
+
+/**
+ A Java-based utility for converting numeric values into their English word
+ representations. Whether you need to convert a small number, a large number
+ with millions and billions, or even a number with decimal places, this utility
+ has you covered.
+ *
+ */
+public final class NumberToWords {
+
+    private NumberToWords() {
+    }
+
+    private static final String[] UNITS = {"", "One", "Two", "Three", "Four", "Five", "Six", "Seven", "Eight", "Nine", "Ten", "Eleven", "Twelve", "Thirteen", "Fourteen", "Fifteen", "Sixteen", "Seventeen", "Eighteen", "Nineteen"};
+
+    private static final String[] TENS = {"", "", "Twenty", "Thirty", "Forty", "Fifty", "Sixty", "Seventy", "Eighty", "Ninety"};
+
+    private static final String[] POWERS = {"", "Thousand", "Million", "Billion", "Trillion"};
+
+    private static final String ZERO = "Zero";
+    private static final String POINT = " Point";
+    private static final String NEGATIVE = "Negative ";
+
+    public static String convert(BigDecimal number) {
+        if (number == null) {
+            return "Invalid Input";
+        }
+
+        // Check for negative sign
+        boolean isNegative = number.signum() < 0;
+
+        // Split the number into whole and fractional parts
+        BigDecimal[] parts = number.abs().divideAndRemainder(BigDecimal.ONE);
+        BigDecimal wholePart = parts[0]; // Keep whole part as BigDecimal
+        String fractionalPartStr = parts[1].compareTo(BigDecimal.ZERO) > 0 ? parts[1].toPlainString().substring(2) : ""; // Get fractional part only if it exists
+
+        // Convert whole part to words
+        StringBuilder result = new StringBuilder();
+        if (isNegative) {
+            result.append(NEGATIVE);
+        }
+        result.append(convertWholeNumberToWords(wholePart));
+
+        // Convert fractional part to words
+        if (!fractionalPartStr.isEmpty()) {
+            result.append(POINT);
+            for (char digit : fractionalPartStr.toCharArray()) {
+                int digitValue = Character.getNumericValue(digit);
+                result.append(" ").append(digitValue == 0 ? ZERO : UNITS[digitValue]);
+            }
+        }
+
+        return result.toString().trim();
+    }
+
+    private static String convertWholeNumberToWords(BigDecimal number) {
+        if (number.compareTo(BigDecimal.ZERO) == 0) {
+            return ZERO;
+        }
+
+        StringBuilder words = new StringBuilder();
+        int power = 0;
+
+        while (number.compareTo(BigDecimal.ZERO) > 0) {
+            // Get the last three digits
+            BigDecimal[] divisionResult = number.divideAndRemainder(BigDecimal.valueOf(1000));
+            int chunk = divisionResult[1].intValue();
+
+            if (chunk > 0) {
+                String chunkWords = convertChunk(chunk);
+                if (power > 0) {
+                    words.insert(0, POWERS[power] + " ");
+                }
+                words.insert(0, chunkWords + " ");
+            }
+
+            number = divisionResult[0]; // Continue with the remaining part
+            power++;
+        }
+
+        return words.toString().trim();
+    }
+
+    private static String convertChunk(int number) {
+        String chunkWords;
+
+        if (number < 20) {
+            chunkWords = UNITS[number];
+        } else if (number < 100) {
+            chunkWords = TENS[number / 10] + (number % 10 > 0 ? " " + UNITS[number % 10] : "");
+        } else {
+            chunkWords = UNITS[number / 100] + " Hundred" + (number % 100 > 0 ? " " + convertChunk(number % 100) : "");
+        }
+
+        return chunkWords;
+    }
+}

src/main/java/com/thealgorithms/conversions/NumberToWords.java

@@ -17,7 +17,7 @@ public static int getMaxValue(int... numbers) {
         }
         int absMax = numbers[0];
         for (int i = 1; i < numbers.length; i++) {
-            if (Math.abs(numbers[i]) > Math.abs(absMax)) {
+            if (Math.abs(numbers[i]) > Math.abs(absMax) || (Math.abs(numbers[i]) == Math.abs(absMax) && numbers[i] > absMax)) {
                 absMax = numbers[i];
             }
         }

src/main/java/com/thealgorithms/maths/AbsoluteMax.java

@@ -19,7 +19,7 @@ public static int getMinValue(int... numbers) {
 
         var absMinWrapper = new Object() { int value = numbers[0]; };
 
-        Arrays.stream(numbers).skip(1).filter(number -> Math.abs(number) < Math.abs(absMinWrapper.value)).forEach(number -> absMinWrapper.value = number);
+        Arrays.stream(numbers).skip(1).filter(number -> Math.abs(number) <= Math.abs(absMinWrapper.value)).forEach(number -> absMinWrapper.value = Math.min(absMinWrapper.value, number));
 
         return absMinWrapper.value;
     }

src/main/java/com/thealgorithms/maths/AbsoluteMin.java

@@ -0,0 +1,59 @@
+package com.thealgorithms.sorts;
+
+/**
+ * Dark Sort algorithm implementation.
+ *
+ * Dark Sort uses a temporary array to count occurrences of elements and
+ * reconstructs the sorted array based on the counts.
+ */
+class DarkSort {
+
+    /**
+     * Sorts the array using the Dark Sort algorithm.
+     *
+     * @param unsorted the array to be sorted
+     * @return sorted array
+     */
+    public Integer[] sort(Integer[] unsorted) {
+        if (unsorted == null || unsorted.length <= 1) {
+            return unsorted;
+        }
+
+        int max = findMax(unsorted); // Find the maximum value in the array
+
+        // Create a temporary array for counting occurrences
+        int[] temp = new int[max + 1];
+
+        // Count occurrences of each element
+        for (int value : unsorted) {
+            temp[value]++;
+        }
+
+        // Reconstruct the sorted array
+        int index = 0;
+        for (int i = 0; i < temp.length; i++) {
+            while (temp[i] > 0) {
+                unsorted[index++] = i;
+                temp[i]--;
+            }
+        }
+
+        return unsorted;
+    }
+
+    /**
+     * Helper method to find the maximum value in an array.
+     *
+     * @param arr the array
+     * @return the maximum value
+     */
+    private int findMax(Integer[] arr) {
+        int max = arr[0];
+        for (int value : arr) {
+            if (value > max) {
+                max = value;
+            }
+        }
+        return max;
+    }
+}

src/main/java/com/thealgorithms/sorts/DarkSort.java

@@ -0,0 +1,60 @@
+package com.thealgorithms.conversions;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.math.BigDecimal;
+import org.junit.jupiter.api.Test;
+
+public class NumberToWordsTest {
+
+    @Test
+    void testNullInput() {
+        assertEquals("Invalid Input", NumberToWords.convert(null), "Null input should return 'Invalid Input'");
+    }
+
+    @Test
+    void testZeroInput() {
+        assertEquals("Zero", NumberToWords.convert(BigDecimal.ZERO), "Zero input should return 'Zero'");
+    }
+
+    @Test
+    void testPositiveWholeNumbers() {
+        assertEquals("One", NumberToWords.convert(BigDecimal.ONE), "1 should convert to 'One'");
+        assertEquals("One Thousand", NumberToWords.convert(new BigDecimal("1000")), "1000 should convert to 'One Thousand'");
+        assertEquals("One Million", NumberToWords.convert(new BigDecimal("1000000")), "1000000 should convert to 'One Million'");
+    }
+
+    @Test
+    void testNegativeWholeNumbers() {
+        assertEquals("Negative One", NumberToWords.convert(new BigDecimal("-1")), "-1 should convert to 'Negative One'");
+        assertEquals("Negative One Thousand", NumberToWords.convert(new BigDecimal("-1000")), "-1000 should convert to 'Negative One Thousand'");
+    }
+
+    @Test
+    void testFractionalNumbers() {
+        assertEquals("Zero Point One Two Three", NumberToWords.convert(new BigDecimal("0.123")), "0.123 should convert to 'Zero Point One Two Three'");
+        assertEquals("Negative Zero Point Four Five Six", NumberToWords.convert(new BigDecimal("-0.456")), "-0.456 should convert to 'Negative Zero Point Four Five Six'");
+    }
+
+    @Test
+    void testLargeNumbers() {
+        assertEquals("Nine Hundred Ninety Nine Million Nine Hundred Ninety Nine Thousand Nine Hundred Ninety Nine", NumberToWords.convert(new BigDecimal("999999999")), "999999999 should convert correctly");
+        assertEquals("One Trillion", NumberToWords.convert(new BigDecimal("1000000000000")), "1000000000000 should convert to 'One Trillion'");
+    }
+
+    @Test
+    void testNegativeLargeNumbers() {
+        assertEquals("Negative Nine Trillion Eight Hundred Seventy Six Billion Five Hundred Forty Three Million Two Hundred Ten Thousand Nine Hundred Eighty Seven", NumberToWords.convert(new BigDecimal("-9876543210987")), "-9876543210987 should convert correctly");
+    }
+
+    @Test
+    void testFloatingPointPrecision() {
+        assertEquals("One Million Point Zero Zero One", NumberToWords.convert(new BigDecimal("1000000.001")), "1000000.001 should convert to 'One Million Point Zero Zero One'");
+    }
+
+    @Test
+    void testEdgeCases() {
+        assertEquals("Zero", NumberToWords.convert(new BigDecimal("-0.0")), "-0.0 should convert to 'Zero'");
+        assertEquals("Zero Point Zero Zero Zero Zero Zero Zero One", NumberToWords.convert(new BigDecimal("1E-7")), "1E-7 should convert to 'Zero Point Zero Zero Zero Zero Zero Zero One'");
+    }
+}

src/test/java/com/thealgorithms/conversions/NumberToWordsTest.java

@@ -19,4 +19,12 @@ void testGetMaxValue() {
     void testGetMaxValueWithNoArguments() {
         assertThrows(IllegalArgumentException.class, AbsoluteMax::getMaxValue);
     }
+
+    @Test
+    void testGetMaxValueWithSameAbsoluteValues() {
+        assertEquals(5, AbsoluteMax.getMaxValue(-5, 5));
+        assertEquals(5, AbsoluteMax.getMaxValue(5, -5));
+        assertEquals(12, AbsoluteMax.getMaxValue(-12, 9, 3, 12, 1));
+        assertEquals(12, AbsoluteMax.getMaxValue(12, 9, 3, -12, 1));
+    }
 }

src/test/java/com/thealgorithms/maths/AbsoluteMaxTest.java

@@ -15,7 +15,13 @@ void testGetMinValue() {
 
     @Test
     void testGetMinValueWithNoArguments() {
-        Exception exception = assertThrows(IllegalArgumentException.class, () -> AbsoluteMin.getMinValue());
+        Exception exception = assertThrows(IllegalArgumentException.class, AbsoluteMin::getMinValue);
         assertEquals("Numbers array cannot be empty", exception.getMessage());
     }
+
+    @Test
+    void testGetMinValueWithSameAbsoluteValues() {
+        assertEquals(-5, AbsoluteMin.getMinValue(-5, 5));
+        assertEquals(-5, AbsoluteMin.getMinValue(5, -5));
+    }
 }

src/test/java/com/thealgorithms/maths/AbsoluteMinTest.java

@@ -0,0 +1,74 @@
+package com.thealgorithms.sorts;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertNull;
+
+import org.junit.jupiter.api.Test;
+
+class DarkSortTest {
+
+    @Test
+    void testSortWithIntegers() {
+        Integer[] unsorted = {5, 3, 8, 6, 2, 7, 4, 1};
+        Integer[] expected = {1, 2, 3, 4, 5, 6, 7, 8};
+
+        DarkSort darkSort = new DarkSort();
+        Integer[] sorted = darkSort.sort(unsorted);
+
+        assertArrayEquals(expected, sorted);
+    }
+
+    @Test
+    void testEmptyArray() {
+        Integer[] unsorted = {};
+        Integer[] expected = {};
+
+        DarkSort darkSort = new DarkSort();
+        Integer[] sorted = darkSort.sort(unsorted);
+
+        assertArrayEquals(expected, sorted);
+    }
+
+    @Test
+    void testSingleElementArray() {
+        Integer[] unsorted = {42};
+        Integer[] expected = {42};
+
+        DarkSort darkSort = new DarkSort();
+        Integer[] sorted = darkSort.sort(unsorted);
+
+        assertArrayEquals(expected, sorted);
+    }
+
+    @Test
+    void testAlreadySortedArray() {
+        Integer[] unsorted = {1, 2, 3, 4, 5};
+        Integer[] expected = {1, 2, 3, 4, 5};
+
+        DarkSort darkSort = new DarkSort();
+        Integer[] sorted = darkSort.sort(unsorted);
+
+        assertArrayEquals(expected, sorted);
+    }
+
+    @Test
+    void testDuplicateElementsArray() {
+        Integer[] unsorted = {4, 2, 7, 2, 1, 4};
+        Integer[] expected = {1, 2, 2, 4, 4, 7};
+
+        DarkSort darkSort = new DarkSort();
+        Integer[] sorted = darkSort.sort(unsorted);
+
+        assertArrayEquals(expected, sorted);
+    }
+
+    @Test
+    void testNullArray() {
+        Integer[] unsorted = null;
+
+        DarkSort darkSort = new DarkSort();
+        Integer[] sorted = darkSort.sort(unsorted);
+
+        assertNull(sorted, "Sorting a null array should return null");
+    }
+}