Sorted Linked List Added (#5519)

* Sorted Linked List added with Javadoc and tests

* "Added comments to SortedLinkedList.java to describe the implementation and provide a reference link."

* Upgraded test from junit 4 to junit 5

* Added space before braces of functions

* Rename SortedlinkedListTest.java to SortedLinkedListTest.java

* made to string null safe

* Updated tail

* "Added assignment of `this.tail` to `newNode` in `SortedLinkedList` class."

* Remove assertions for minValue and maxValue in empty list test

* tried to get link updated

* "Fixed whitespace and formatting issues in SortedLinkedList.java and SortedLinkedListTest.java"

* formatting of test file corrected

* Removed few whitespaces

* Addressed comments by alxkm

* "Updated toString method to include brackets and removed default Node constructor."

* tests updated

Author: mjk22071998

src/main/java/com/thealgorithms/datastructures/lists/SortedLinkedList.java

@@ -0,0 +1,141 @@
+package com.thealgorithms.datastructures.lists;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * A SortedLinkedList is a data structure that maintains a sorted list of elements.
+ * Elements are ordered based on their natural ordering or by a Comparator provided at the time of creation.
+ * This implementation uses a singly linked list to store the elements.
+ * Further details can be found on this link
+ * https://runestone.academy/ns/books/published/cppds/LinearLinked/ImplementinganOrderedList.html
+ */
+public class SortedLinkedList {
+    private Node head;
+    private Node tail;
+
+    public SortedLinkedList() {
+        this.head = null;
+        this.tail = null;
+    }
+
+    /**
+     * Inserts a new element into the sorted linked list.
+     * @param value the value to be inserted
+     */
+    public void insert(int value) {
+        Node newNode = new Node(value);
+        if (head == null) {
+            this.head = newNode;
+            this.tail = newNode;
+        } else if (value < head.value) {
+            newNode.next = this.head;
+            this.head = newNode;
+        } else if (value > tail.value) {
+            this.tail.next = newNode;
+            this.tail = newNode;
+        } else {
+            Node temp = head;
+            while (temp.next != null && temp.next.value < value) {
+                temp = temp.next;
+            }
+            newNode.next = temp.next;
+            temp.next = newNode;
+            if (newNode.next == null) {
+                this.tail = newNode;
+            }
+        }
+    }
+
+    /**
+     * Displays the elements of the sorted linked list.
+     */
+    public void display() {
+        System.out.println(this.toString());
+    }
+
+    /**
+     * Deletes the first occurrence of the specified element in the sorted linked list.
+     * @param value the value to be deleted
+     * @return true if the element is found and deleted, false otherwise
+     */
+    public boolean delete(int value) {
+        if (this.head == null) {
+            return false;
+        } else if (this.head.value == value) {
+            if (this.head.next == null) {
+                this.head = null;
+                this.tail = null;
+            } else {
+                this.head = this.head.next;
+            }
+            return true;
+        } else {
+            Node temp = this.head;
+            while (temp.next != null) {
+                if (temp.next.value == value) {
+                    if (temp.next == this.tail) {
+                        this.tail = temp;
+                    }
+                    temp.next = temp.next.next;
+                    return true;
+                }
+                temp = temp.next;
+            }
+            return false;
+        }
+    }
+
+    /**
+     * Searches for the specified element in the sorted linked list.
+     * @param value the value to be searched
+     * @return true if the element is found, false otherwise
+     */
+    public boolean search(int value) {
+        Node temp = this.head;
+        while (temp != null) {
+            if (temp.value == value) {
+                return true;
+            }
+            temp = temp.next;
+        }
+        return false;
+    }
+
+    /**
+     * Checks if the sorted linked list is empty.
+     * @return true if the list is empty, false otherwise
+     */
+    public boolean isEmpty() {
+        return head == null;
+    }
+    /**
+     * Returns a string representation of the sorted linked list.
+     * @return a string representation of the sorted linked list
+     */
+    @Override
+    public String toString() {
+        if (this.head != null) {
+            List<String> elements = new ArrayList<>();
+            Node temp = this.head;
+            while (temp != null) {
+                elements.add(String.valueOf(temp.value));
+                temp = temp.next;
+            }
+            return "[" + String.join(", ", elements) + "]";
+
+        } else {
+            return "[]";
+        }
+    }
+
+    public final class Node {
+        public final int value;
+        public Node next;
+
+        public Node(int value) {
+            this.value = value;
+            this.next = null;
+        }
+    }
+}

src/test/java/com/thealgorithms/datastructures/lists/SortedLinkedListTest.java

@@ -0,0 +1,67 @@
+package com.thealgorithms.datastructures.lists;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.api.Test;
+
+public class SortedLinkedListTest {
+
+    @Test
+    public void testInsert() {
+        SortedLinkedList list = new SortedLinkedList();
+        list.insert(5);
+        list.insert(3);
+        list.insert(7);
+        assertEquals("[3, 5, 7]", list.toString());
+    }
+
+    @Test
+    public void testDelete() {
+        SortedLinkedList list = new SortedLinkedList();
+        list.insert(5);
+        list.insert(3);
+        list.insert(7);
+        assertTrue(list.delete(5));
+        assertEquals("[3, 7]", list.toString());
+        assertFalse(list.delete(10));
+    }
+
+    @Test
+    public void testSearch() {
+        SortedLinkedList list = new SortedLinkedList();
+        list.insert(5);
+        list.insert(3);
+        list.insert(7);
+        assertTrue(list.search(5));
+        assertFalse(list.search(10));
+    }
+    @Test
+    public void testEmptyList() {
+        SortedLinkedList list = new SortedLinkedList();
+        assertEquals("[]", list.toString());
+        assertFalse(list.delete(5));
+        assertFalse(list.search(5));
+    }
+    @Test
+    public void testIsEmptyOnEmptyList() {
+        SortedLinkedList list = new SortedLinkedList();
+        assertTrue(list.isEmpty());
+    }
+
+    @Test
+    public void testIsEmptyOnNonEmptyList() {
+        SortedLinkedList list = new SortedLinkedList();
+        list.insert(10);
+        assertFalse(list.isEmpty());
+    }
+
+    @Test
+    public void testIsEmptyAfterDeletion() {
+        SortedLinkedList list = new SortedLinkedList();
+        list.insert(10);
+        list.delete(10);
+        assertTrue(list.isEmpty());
+    }
+}