Merge branch 'master' into add-longest-substring

Author: siriak

DIRECTORY.md

@@ -321,6 +321,7 @@
             * [BinaryAddition](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/BinaryAddition.java)
             * [CoinChange](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/CoinChange.java)
             * [DigitSeparation](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/DigitSeparation.java)
+            * [EgyptianFraction](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/EgyptianFraction.java)
             * [FractionalKnapsack](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/FractionalKnapsack.java)
             * [GaleShapley](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/GaleShapley.java)
             * [JobSequencing](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/JobSequencing.java)
@@ -351,6 +352,7 @@
             * [BinaryPow](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/BinaryPow.java)
             * [BinomialCoefficient](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/BinomialCoefficient.java)
             * [Ceil](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/Ceil.java)
+            * [ChineseRemainderTheorem](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/ChineseRemainderTheorem.java)
             * [CircularConvolutionFFT](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/CircularConvolutionFFT.java)
             * [CollatzConjecture](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/CollatzConjecture.java)
             * [Combinations](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/Combinations.java)
@@ -568,6 +570,8 @@
             * [TernarySearch](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/searches/TernarySearch.java)
             * [UnionFind](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/searches/UnionFind.java)
             * [UpperBound](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/searches/UpperBound.java)
+          * slidingwindow
+            * [MaxSumKSizeSubarray](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/slidingwindow/MaxSumKSizeSubarray.java)
           * sorts
             * [AdaptiveMergeSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/AdaptiveMergeSort.java)
             * [BeadSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/BeadSort.java)
@@ -826,6 +830,7 @@
               * [HashMapCuckooHashingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/hashmap/HashMapCuckooHashingTest.java)
             * heaps
               * [FibonacciHeapTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/heaps/FibonacciHeapTest.java)
+              * [GenericHeapTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/heaps/GenericHeapTest.java)
               * [LeftistHeapTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/heaps/LeftistHeapTest.java)
             * lists
               * [CircleLinkedListTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/lists/CircleLinkedListTest.java)
@@ -942,6 +947,7 @@
             * [BinaryAdditionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/BinaryAdditionTest.java)
             * [CoinChangeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/CoinChangeTest.java)
             * [DigitSeparationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/DigitSeparationTest.java)
+            * [EgyptianFractionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/EgyptianFractionTest.java)
             * [FractionalKnapsackTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/FractionalKnapsackTest.java)
             * [GaleShapleyTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/GaleShapleyTest.java)
             * [JobSequencingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/JobSequencingTest.java)
@@ -969,6 +975,7 @@
             * [BinaryPowTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/BinaryPowTest.java)
             * [BinomialCoefficientTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/BinomialCoefficientTest.java)
             * [CeilTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/CeilTest.java)
+            * [ChineseRemainderTheoremTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/ChineseRemainderTheoremTest.java)
             * [CollatzConjectureTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/CollatzConjectureTest.java)
             * [CombinationsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/CombinationsTest.java)
             * [ConvolutionFFTTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/ConvolutionFFTTest.java)
@@ -1155,6 +1162,8 @@
             * [TestSearchInARowAndColWiseSortedMatrix](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/TestSearchInARowAndColWiseSortedMatrix.java)
             * [UnionFindTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/UnionFindTest.java)
             * [UpperBoundTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/UpperBoundTest.java)
+          * slidingwindow
+            * [MaxSumKSizeSubarrayTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/slidingwindow/MaxSumKSizeSubarrayTest.java)
           * sorts
             * [AdaptiveMergeSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/AdaptiveMergeSortTest.java)
             * [BeadSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/BeadSortTest.java)

src/main/java/com/thealgorithms/datastructures/heaps/GenericHeap.java

@@ -9,6 +9,10 @@ public class GenericHeap<T extends Comparable<T>> {
     HashMap<T, Integer> map = new HashMap<>();
 
     public void add(T item) {
+        if (item == null) {
+            throw new IllegalArgumentException("Cannot insert null into the heap.");
+        }
+
         this.data.add(item);
         map.put(item, this.data.size() - 1); //
         upHeapify(this.data.size() - 1);

src/main/java/com/thealgorithms/datastructures/lists/README.md

@@ -1,7 +1,7 @@
 ## Linked List
 ### Description
 
-LinkedList is a data structure in which data is stored in a linear manner. It usually contains a data field and a link to the memory location of the next mode.
+LinkedList is a data structure in which data is stored in a linear manner. It usually contains a data field and a link to the memory location of the next node.
 
 ### Structure
 

src/main/java/com/thealgorithms/greedyalgorithms/EgyptianFraction.java

@@ -0,0 +1,35 @@
+package com.thealgorithms.greedyalgorithms;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Class to represent a fraction as a sum of unique unit fractions.
+ * Example:
+ * 2/3 = 1/2 + 1/6
+ * 3/10 = 1/4 + 1/20
+ *
+ * @author Hardvan
+ */
+public final class EgyptianFraction {
+    private EgyptianFraction() {
+    }
+
+    /**
+     * Calculates the Egyptian Fraction representation of a given fraction.
+     *
+     * @param numerator   the numerator of the fraction
+     * @param denominator the denominator of the fraction
+     * @return List of unit fractions represented as strings "1/x"
+     */
+    public static List<String> getEgyptianFraction(int numerator, int denominator) {
+        List<String> result = new ArrayList<>();
+        while (numerator != 0) {
+            int x = (int) Math.ceil((double) denominator / numerator);
+            result.add("1/" + x);
+            numerator = numerator * x - denominator;
+            denominator = denominator * x;
+        }
+        return result;
+    }
+}

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

@@ -0,0 +1,84 @@
+package com.thealgorithms.maths;
+
+import java.util.List;
+
+/**
+ * @brief Implementation of the Chinese Remainder Theorem (CRT) algorithm
+ * @details
+ * The Chinese Remainder Theorem (CRT) is used to solve systems of
+ * simultaneous congruences. Given several pairwise coprime moduli
+ * and corresponding remainders, the algorithm finds the smallest
+ * positive solution.
+ */
+public final class ChineseRemainderTheorem {
+    private ChineseRemainderTheorem() {
+    }
+
+    /**
+     * @brief Solves the Chinese Remainder Theorem problem.
+     * @param remainders The list of remainders.
+     * @param moduli The list of pairwise coprime moduli.
+     * @return The smallest positive solution that satisfies all the given congruences.
+     */
+    public static int solveCRT(List<Integer> remainders, List<Integer> moduli) {
+        int product = 1;
+        int result = 0;
+
+        // Calculate the product of all moduli
+        for (int mod : moduli) {
+            product *= mod;
+        }
+
+        // Apply the formula for each congruence
+        for (int i = 0; i < moduli.size(); i++) {
+            int partialProduct = product / moduli.get(i);
+            int inverse = modInverse(partialProduct, moduli.get(i));
+            result += remainders.get(i) * partialProduct * inverse;
+        }
+
+        // Adjust result to be the smallest positive solution
+        result = result % product;
+        if (result < 0) {
+            result += product;
+        }
+
+        return result;
+    }
+
+    /**
+     * @brief Computes the modular inverse of a number with respect to a modulus using
+     * the Extended Euclidean Algorithm.
+     * @param a The number for which to find the inverse.
+     * @param m The modulus.
+     * @return The modular inverse of a modulo m.
+     */
+    private static int modInverse(int a, int m) {
+        int m0 = m;
+        int x0 = 0;
+        int x1 = 1;
+
+        if (m == 1) {
+            return 0;
+        }
+
+        while (a > 1) {
+            int q = a / m;
+            int t = m;
+
+            // m is remainder now, process same as Euclid's algorithm
+            m = a % m;
+            a = t;
+            t = x0;
+
+            x0 = x1 - q * x0;
+            x1 = t;
+        }
+
+        // Make x1 positive
+        if (x1 < 0) {
+            x1 += m0;
+        }
+
+        return x1;
+    }
+}

src/test/java/com/thealgorithms/datastructures/heaps/GenericHeapTest.java

@@ -0,0 +1,126 @@
+package com.thealgorithms.datastructures.heaps;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+public class GenericHeapTest {
+
+    private GenericHeap<Integer> heap;
+
+    @BeforeEach
+    public void setUp() {
+        heap = new GenericHeap<>();
+    }
+
+    @Test
+    public void testGenericHeapAddAndGet() {
+        heap.add(19);
+        heap.add(36);
+        heap.add(100);
+        heap.add(-17);
+        heap.add(3);
+
+        // Check that the largest element (100) is at the top of the heap
+        assertEquals(100, heap.get());
+    }
+
+    @Test
+    public void testGenericHeapRemove() {
+        heap.add(19);
+        heap.add(36);
+        heap.add(100);
+        heap.add(-17);
+        heap.add(3);
+
+        // Verify that the largest element is removed correctly
+        assertEquals(100, heap.remove());
+
+        // The new element at the top should be 36
+        assertEquals(36, heap.get());
+
+        // Check that the size is correct after removal
+        assertEquals(4, heap.size());
+    }
+
+    @Test
+    public void testGenericHeapSize() {
+        assertTrue(heap.isEmpty());
+
+        heap.add(10);
+        heap.add(20);
+
+        // Check that the size is correct
+        assertEquals(2, heap.size());
+
+        heap.remove();
+
+        // After removal, the size should be 1
+        assertEquals(1, heap.size());
+    }
+
+    @Test
+    public void testGenericHeapIsEmpty() {
+        // Verify that the heap is initially empty
+        assertTrue(heap.isEmpty());
+
+        heap.add(15);
+
+        // Now the heap should not be empty
+        assertFalse(heap.isEmpty());
+
+        heap.remove();
+
+        // After removing the one element, it should be empty again
+        assertTrue(heap.isEmpty());
+    }
+
+    @Test
+    public void testGenericHeapUpdatePriority() {
+        heap.add(19);
+        heap.add(36);
+        heap.add(100);
+        heap.add(-17);
+        heap.add(3);
+
+        // Verify that the largest element initially is 100
+        assertEquals(100, heap.get());
+
+        heap.remove();
+
+        // Simulates a change in priority by increasing the value of 100 to 44
+        heap.add(44);
+
+        // Now, the new high should be 25
+        assertEquals(44, heap.get());
+    }
+
+    @Test
+    public void testGenericHeapRemoveUntilEmpty() {
+        heap.add(5);
+        heap.add(3);
+        heap.add(4);
+        heap.add(1);
+        heap.add(2);
+
+        // Remove all items and check that they are removed in descending order
+        assertEquals(5, heap.remove());
+        assertEquals(4, heap.remove());
+        assertEquals(3, heap.remove());
+        assertEquals(2, heap.remove());
+        assertEquals(1, heap.remove());
+
+        // Empty heap
+        assertTrue(heap.isEmpty());
+    }
+
+    @Test
+    public void testGenericHeapAddNullItem() {
+        // Check null item
+        assertThrows(IllegalArgumentException.class, () -> { heap.add(null); });
+    }
+}

src/test/java/com/thealgorithms/greedyalgorithms/EgyptianFractionTest.java

@@ -0,0 +1,22 @@
+package com.thealgorithms.greedyalgorithms;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.List;
+import java.util.stream.Stream;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+public class EgyptianFractionTest {
+
+    @ParameterizedTest
+    @MethodSource("fractionProvider")
+    public void testGetEgyptianFraction(int numerator, int denominator, List<String> expected) {
+        assertEquals(expected, EgyptianFraction.getEgyptianFraction(numerator, denominator));
+    }
+
+    private static Stream<Arguments> fractionProvider() {
+        return Stream.of(Arguments.of(2, 3, List.of("1/2", "1/6")), Arguments.of(3, 10, List.of("1/4", "1/20")), Arguments.of(1, 3, List.of("1/3")), Arguments.of(1, 2, List.of("1/2")), Arguments.of(4, 13, List.of("1/4", "1/18", "1/468")));
+    }
+}