Merge branch 'master' of github.com:eugenp/tutorials

algorithms-miscellaneous-3/README.md

@@ -13,6 +13,5 @@ This module contains articles about algorithms. Some classes of algorithms, e.g.
 - [Checking if a Java Graph has a Cycle](https://www.baeldung.com/java-graph-has-a-cycle)
 - [A Guide to the Folding Technique in Java](https://www.baeldung.com/folding-hashing-technique)
 - [Creating a Triangle with for Loops in Java](https://www.baeldung.com/java-print-triangle)
-- [Efficient Word Frequency Calculator in Java](https://www.baeldung.com/java-word-frequency)
 - [The K-Means Clustering Algorithm in Java](https://www.baeldung.com/java-k-means-clustering-algorithm)
 - More articles: [[<-- prev]](/algorithms-miscellaneous-2) [[next -->]](/algorithms-miscellaneous-4)

algorithms-miscellaneous-5/README.md

@@ -15,9 +15,5 @@ This module contains articles about algorithms. Some classes of algorithms, e.g.
 - [Maximum Subarray Problem](https://www.baeldung.com/java-maximum-subarray)
 - [How to Merge Two Sorted Arrays](https://www.baeldung.com/java-merge-sorted-arrays)
 - [Median of Stream of Integers using Heap](https://www.baeldung.com/java-stream-integers-median-using-heap)
-- [Kruskal’s Algorithm for Spanning Trees](https://www.baeldung.com/java-spanning-trees-kruskal)
-- [Balanced Brackets Algorithm in Java](https://www.baeldung.com/java-balanced-brackets-algorithm)
-- [Efficiently Merge Sorted Java Sequences](https://www.baeldung.com/java-merge-sorted-sequences)
-- [Introduction to Greedy Algorithms with Java](https://www.baeldung.com/java-greedy-algorithms)
-- [The Caesar Cipher in Java](https://www.baeldung.com/java-caesar-cipher)
-- More articles: [[<-- prev]](/../algorithms-miscellaneous-4)
+- More articles: [[<-- prev]](/../algorithms-miscellaneous-4) [[next -->]](/../algorithms-miscellaneous-6)
+

algorithms-miscellaneous-5/pom.xml

@@ -25,12 +25,6 @@
             <artifactId>commons-math3</artifactId>
             <version>${commons-math3.version}</version>
         </dependency>
-        <dependency>
-            <groupId>org.projectlombok</groupId>
-            <artifactId>lombok</artifactId>
-            <version>${lombok.version}</version>
-            <scope>provided</scope>
-        </dependency>
         <dependency>
             <groupId>pl.allegro.finance</groupId>
             <artifactId>tradukisto</artifactId>

algorithms-miscellaneous-6/README.md

@@ -0,0 +1,10 @@
+### Relevant Articles:
+
+- [Boruvka’s Algorithm for Minimum Spanning Trees](https://www.baeldung.com/java-boruvka-algorithm)
+- [Gradient Descent in Java](https://www.baeldung.com/java-gradient-descent)
+- [Kruskal’s Algorithm for Spanning Trees](https://www.baeldung.com/java-spanning-trees-kruskal)
+- [Balanced Brackets Algorithm in Java](https://www.baeldung.com/java-balanced-brackets-algorithm)
+- [Efficiently Merge Sorted Java Sequences](https://www.baeldung.com/java-merge-sorted-sequences)
+- [Introduction to Greedy Algorithms with Java](https://www.baeldung.com/java-greedy-algorithms)
+- [The Caesar Cipher in Java](https://www.baeldung.com/java-caesar-cipher)
+- More articles: [[<-- prev]](/../algorithms-miscellaneous-5)

algorithms-miscellaneous-6/pom.xml

@@ -18,10 +18,35 @@
             <artifactId>guava</artifactId>
             <version>${guava.version}</version>
         </dependency>
+        <dependency>
+            <groupId>org.junit.platform</groupId>
+            <artifactId>junit-platform-commons</artifactId>
+            <version>${junit.platform.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.assertj</groupId>
+            <artifactId>assertj-core</artifactId>
+            <version>${org.assertj.core.version}</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.projectlombok</groupId>
+            <artifactId>lombok</artifactId>
+            <version>${lombok.version}</version>
+            <scope>provided</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.apache.commons</groupId>
+            <artifactId>commons-math3</artifactId>
+            <version>${commons-math3.version}</version>
+        </dependency>
     </dependencies>
     
     <properties>
         <guava.version>28.1-jre</guava.version>
+        <org.assertj.core.version>3.9.0</org.assertj.core.version>
+        <junit.platform.version>1.6.0</junit.platform.version>
+        <commons-math3.version>3.6.1</commons-math3.version>
     </properties>
 
 </project>

algorithms-miscellaneous-6/src/main/java/com/baeldung/algorithms/minheapmerge/HeapNode.java

@@ -1,13 +1,13 @@
-package com.baeldung.algorithms.minheapmerge;
-
-public class HeapNode {
-
-    int element;
-    int arrayIndex;
-    int nextElementIndex = 1;
-
-    public HeapNode(int element, int arrayIndex) {
-        this.element = element;
-        this.arrayIndex = arrayIndex;
-    }
-}
+package com.baeldung.algorithms.minheapmerge;
+
+public class HeapNode {
+
+    int element;
+    int arrayIndex;
+    int nextElementIndex = 1;
+
+    public HeapNode(int element, int arrayIndex) {
+        this.element = element;
+        this.arrayIndex = arrayIndex;
+    }
+}

algorithms-miscellaneous-6/src/main/java/com/baeldung/algorithms/minheapmerge/MinHeap.java

@@ -1,88 +1,88 @@
-package com.baeldung.algorithms.minheapmerge;
-
-public class MinHeap {
-
-    HeapNode[] heapNodes;
-
-    public MinHeap(HeapNode heapNodes[]) {
-        this.heapNodes = heapNodes;
-        heapifyFromLastLeafsParent();
-    }
-
-    void heapifyFromLastLeafsParent() {
-        int lastLeafsParentIndex = getParentNodeIndex(heapNodes.length);
-        while (lastLeafsParentIndex >= 0) {
-            heapify(lastLeafsParentIndex);
-            lastLeafsParentIndex--;
-        }
-    }
-
-    void heapify(int index) {
-        int leftNodeIndex = getLeftNodeIndex(index);
-        int rightNodeIndex = getRightNodeIndex(index);
-        int smallestElementIndex = index;
-        if (leftNodeIndex < heapNodes.length && heapNodes[leftNodeIndex].element < heapNodes[index].element) {
-            smallestElementIndex = leftNodeIndex;
-        }
-        if (rightNodeIndex < heapNodes.length && heapNodes[rightNodeIndex].element < heapNodes[smallestElementIndex].element) {
-            smallestElementIndex = rightNodeIndex;
-        }
-        if (smallestElementIndex != index) {
-            swap(index, smallestElementIndex);
-            heapify(smallestElementIndex);
-        }
-    }
-
-    int getParentNodeIndex(int index) {
-        return (index - 1) / 2;
-    }
-
-    int getLeftNodeIndex(int index) {
-        return (2 * index + 1);
-    }
-
-    int getRightNodeIndex(int index) {
-        return (2 * index + 2);
-    }
-
-    HeapNode getRootNode() {
-        return heapNodes[0];
-    }
-
-    void heapifyFromRoot() {
-        heapify(0);
-    }
-
-    void swap(int i, int j) {
-        HeapNode temp = heapNodes[i];
-        heapNodes[i] = heapNodes[j];
-        heapNodes[j] = temp;
-    }
-    
-    static int[] merge(int[][] array) {
-        HeapNode[] heapNodes = new HeapNode[array.length];
-        int resultingArraySize = 0;
-
-        for (int i = 0; i < array.length; i++) {
-            HeapNode node = new HeapNode(array[i][0], i);
-            heapNodes[i] = node;
-            resultingArraySize += array[i].length;
-        }
-        
-        MinHeap minHeap = new MinHeap(heapNodes);
-        int[] resultingArray = new int[resultingArraySize];
-
-        for (int i = 0; i < resultingArraySize; i++) {
-            HeapNode root = minHeap.getRootNode();
-            resultingArray[i] = root.element;
-
-            if (root.nextElementIndex < array[root.arrayIndex].length) {
-                root.element = array[root.arrayIndex][root.nextElementIndex++];
-            } else {
-                root.element = Integer.MAX_VALUE;
-            }
-            minHeap.heapifyFromRoot();
-        }
-        return resultingArray;
-    }
-}
+package com.baeldung.algorithms.minheapmerge;
+
+public class MinHeap {
+
+    HeapNode[] heapNodes;
+
+    public MinHeap(HeapNode heapNodes[]) {
+        this.heapNodes = heapNodes;
+        heapifyFromLastLeafsParent();
+    }
+
+    void heapifyFromLastLeafsParent() {
+        int lastLeafsParentIndex = getParentNodeIndex(heapNodes.length);
+        while (lastLeafsParentIndex >= 0) {
+            heapify(lastLeafsParentIndex);
+            lastLeafsParentIndex--;
+        }
+    }
+
+    void heapify(int index) {
+        int leftNodeIndex = getLeftNodeIndex(index);
+        int rightNodeIndex = getRightNodeIndex(index);
+        int smallestElementIndex = index;
+        if (leftNodeIndex < heapNodes.length && heapNodes[leftNodeIndex].element < heapNodes[index].element) {
+            smallestElementIndex = leftNodeIndex;
+        }
+        if (rightNodeIndex < heapNodes.length && heapNodes[rightNodeIndex].element < heapNodes[smallestElementIndex].element) {
+            smallestElementIndex = rightNodeIndex;
+        }
+        if (smallestElementIndex != index) {
+            swap(index, smallestElementIndex);
+            heapify(smallestElementIndex);
+        }
+    }
+
+    int getParentNodeIndex(int index) {
+        return (index - 1) / 2;
+    }
+
+    int getLeftNodeIndex(int index) {
+        return (2 * index + 1);
+    }
+
+    int getRightNodeIndex(int index) {
+        return (2 * index + 2);
+    }
+
+    HeapNode getRootNode() {
+        return heapNodes[0];
+    }
+
+    void heapifyFromRoot() {
+        heapify(0);
+    }
+
+    void swap(int i, int j) {
+        HeapNode temp = heapNodes[i];
+        heapNodes[i] = heapNodes[j];
+        heapNodes[j] = temp;
+    }
+    
+    static int[] merge(int[][] array) {
+        HeapNode[] heapNodes = new HeapNode[array.length];
+        int resultingArraySize = 0;
+
+        for (int i = 0; i < array.length; i++) {
+            HeapNode node = new HeapNode(array[i][0], i);
+            heapNodes[i] = node;
+            resultingArraySize += array[i].length;
+        }
+        
+        MinHeap minHeap = new MinHeap(heapNodes);
+        int[] resultingArray = new int[resultingArraySize];
+
+        for (int i = 0; i < resultingArraySize; i++) {
+            HeapNode root = minHeap.getRootNode();
+            resultingArray[i] = root.element;
+
+            if (root.nextElementIndex < array[root.arrayIndex].length) {
+                root.element = array[root.arrayIndex][root.nextElementIndex++];
+            } else {
+                root.element = Integer.MAX_VALUE;
+            }
+            minHeap.heapifyFromRoot();
+        }
+        return resultingArray;
+    }
+}

algorithms-miscellaneous-6/src/test/java/com/baeldung/algorithms/minheapmerge/MinHeapUnitTest.java

@@ -1,22 +1,22 @@
-package com.baeldung.algorithms.minheapmerge;
-
-import static org.hamcrest.CoreMatchers.equalTo;
-import static org.hamcrest.CoreMatchers.is;
-import static org.junit.Assert.assertThat;
-
-import org.junit.Test;
-
-public class MinHeapUnitTest {
-
-    private final int[][] inputArray = { { 0, 6 }, { 1, 5, 10, 100 }, { 2, 4, 200, 650 } };
-    private final int[] expectedArray = { 0, 1, 2, 4, 5, 6, 10, 100, 200, 650 };
-
-    @Test
-    public void givenSortedArrays_whenMerged_thenShouldReturnASingleSortedarray() {
-        int[] resultArray = MinHeap.merge(inputArray);
-        
-        assertThat(resultArray.length, is(equalTo(10)));
-        assertThat(resultArray, is(equalTo(expectedArray)));
-    }
-    
-}
+package com.baeldung.algorithms.minheapmerge;
+
+import static org.hamcrest.CoreMatchers.equalTo;
+import static org.hamcrest.CoreMatchers.is;
+import static org.junit.Assert.assertThat;
+
+import org.junit.Test;
+
+public class MinHeapUnitTest {
+
+    private final int[][] inputArray = { { 0, 6 }, { 1, 5, 10, 100 }, { 2, 4, 200, 650 } };
+    private final int[] expectedArray = { 0, 1, 2, 4, 5, 6, 10, 100, 200, 650 };
+
+    @Test
+    public void givenSortedArrays_whenMerged_thenShouldReturnASingleSortedarray() {
+        int[] resultArray = MinHeap.merge(inputArray);
+        
+        assertThat(resultArray.length, is(equalTo(10)));
+        assertThat(resultArray, is(equalTo(expectedArray)));
+    }
+    
+}

algorithms-sorting-2/README.md

@@ -1,3 +1,7 @@
 ### Relevant Articles:
 
+- [Sorting a String Alphabetically in Java](https://www.baeldung.com/java-sort-string-alphabetically)
+- [Sorting Strings by Contained Numbers in Java](https://www.baeldung.com/java-sort-strings-contained-numbers)
+- [How an In-Place Sorting Algorithm Works](https://www.baeldung.com/java-in-place-sorting)
 - [Partitioning and Sorting Arrays with Many Repeated Entries](https://www.baeldung.com/java-sorting-arrays-with-repeated-entries)
+- More articles: [[<-- prev]](/algorithms-sorting)

algorithms-sorting-2/src/main/java/com/baeldung/algorithms/bynumber/NaturalOrderComparators.java

@@ -1,4 +1,4 @@
-package com.baeldung.algorithms.sort.bynumber;
+package com.baeldung.algorithms.bynumber;
 
 import java.util.Comparator;
 

algorithms-sorting-2/src/test/java/com/baeldung/algorithms/bynumber/NaturalOrderComparatorsUnitTest.java

@@ -1,6 +1,5 @@
-package com.baeldung.algorithms.sort.bynumber;
+package com.baeldung.algorithms.bynumber;
 
-import com.baeldung.algorithms.sort.bynumber.NaturalOrderComparators;
 import org.junit.Test;
 
 import java.util.ArrayList;