feat(LinkedListDemo1): add examples of sorting and removing elements in LinkedList

What
- Created `LinkedListDemo1` to demonstrate:
  - Sorting a `LinkedList<Integer>` using `sort(null)` (natural ordering).
  - Removing even numbers with `removeIf(predicate)`.
  - Removing all elements in one list that exist in another using `removeAll()`.
- Added examples with both integers and strings.

Why
- Show practical `LinkedList` operations beyond basic add/get:
  - Sorting in-place with natural order.
  - Using `removeIf` for conditional removal (functional style).
  - Using `removeAll` to bulk-remove a set of elements.
- Reinforces that `LinkedList` supports all `List` interface operations, not just queue-like ones.

How
- Built an integer `LinkedList` with mixed values.
- Called `linkedList.sort(null)` to apply natural ascending sort.
- Used `linkedList.removeIf(x -> x % 2 == 0)` to filter odd numbers.
- Created two string `LinkedList`s: `animals` and `animalsToRemove`.
- Called `animals.removeAll(animalsToRemove)` to delete specific elements.
- Printed intermediate results after each operation.

Logic
1. Insert values `[1,2,3,4,5,7,6,8,9,10,44,46,70]`.
2. Sort → `[1,2,3,4,5,6,7,8,9,10,44,46,70]`.
3. Remove evens → `[1,3,5,7,9]`.
4. On `animals`: start `[Cat, Dog, Elephant, lion]`.
5. Remove all `["Dog","lion"]` → `[Cat, Elephant]`.

Complexity
- `sort()` → O(n log n), uses TimSort.
- `removeIf()` → O(n), traverses once.
- `removeAll()` → O(n*m) worst case (n = size of list, m = size of removal list), though optimized internally via hashing for certain collections.
- LinkedList operations like add/remove at ends are O(1); traversal-based ones (like sort or indexed access) are slower (O(n)).

Applications
- Filtering collections by condition (removeIf).
- Bulk removal (removeAll) for lists that need to sync with others.
- Sorting data stored in LinkedList, though usually ArrayList is more efficient for sorting and random access.

Notes
- `LinkedList` implements `List`, `Deque`, `Queue`.
- `sort(null)` means natural ordering; can pass a `Comparator` for custom order.
- `removeIf` is a Java 8 feature; more concise than manual iteration.

Signed-off-by: https://github.com/Someshdiwan <[email protected]>

Author: Someshdiwan

Section25CollectionFramework/src/ListDemo/ArrayListLinkedListStack/RemoveEvenFromLinkedList.java renamed to Section 25 Collections Frameworks/List Interface/LinkedList/src/LinkedListDemo1.java

@@ -1,9 +1,7 @@
-package ListDemo.ArrayListLinkedListStack;
-
 import java.util.Arrays;
 import java.util.LinkedList;
 
-public class RemoveEvenFromLinkedList {
+public class LinkedListDemo1 {
     public static void main(String[] args) {
         LinkedList<Integer> linkedList = new LinkedList<>();
         linkedList.add(1);
@@ -20,12 +18,12 @@ public static void main(String[] args) {
         linkedList.add(46);
         linkedList.add(70);
 
-        linkedList.sort(null); //Natural order of the sorting.
+        linkedList.sort(null); // Natural order of the sorting.
         System.out.println(linkedList);
 
-        //Removing Even Numbers from Linked List.
-        linkedList.removeIf(x-> x%2==0);
-        System.out.println("Removed Even Numbers From LL: "+linkedList);
+        // Removing Even Numbers from Linked List.
+        linkedList.removeIf(x-> x % 2 == 0);
+        System.out.println("Removed Even Numbers From Linked List: " + linkedList);
 
 
         LinkedList<String> animals = new LinkedList<>(Arrays.asList("Cat","Dog","Elephant","lion"));
@@ -34,4 +32,4 @@ public static void main(String[] args) {
         animals.removeAll(animalsToRemove);
         System.out.println(animals);
     }
-}
+}