Move all occurrences of an element to end in a linked list

// C# program to move all occurrences of a
// given key to end.
using System;

class GFG {

    // A Linked list Node
    public class Node {
        public int data;
        public Node next;
    }

    // A utility function to create a new node.
    static Node newNode(int x)
    {
        Node temp = new Node();
        temp.data = x;
        temp.next = null;
        return temp;
    }

    // Utility function to print the elements
    // in Linked list
    static void printList(Node head)
    {
        Node temp = head;
        while (temp != null) {
            Console.Write("{0} ", temp.data);
            temp = temp.next;
        }
        Console.Write("\n");
    }

    // Moves all occurrences of given key to
    // end of linked list.
    static void moveToEnd(Node head, int key)
    {
        // Keeps track of locations where key
        // is present.
        Node pKey = head;

        // Traverse list
        Node pCrawl = head;
        while (pCrawl != null) {
            // If current pointer is not same as pointer
            // to a key location, then we must have found
            // a key in linked list. We swap data of pCrawl
            // and pKey and move pKey to next position.
            if (pCrawl != pKey && pCrawl.data != key) {
                pKey.data = pCrawl.data;
                pCrawl.data = key;
                pKey = pKey.next;
            }

            // Find next position where key is present
            if (pKey.data != key)
                pKey = pKey.next;

            // Moving to next Node
            pCrawl = pCrawl.next;
        }
    }

    // Driver code
    public static void Main(String[] args)
    {
        Node head = newNode(10);
        head.next = newNode(20);
        head.next.next = newNode(10);
        head.next.next.next = newNode(30);
        head.next.next.next.next = newNode(40);
        head.next.next.next.next.next = newNode(10);
        head.next.next.next.next.next.next = newNode(60);

        Console.Write("Before moveToEnd(), the Linked list is\n");
        printList(head);

        int key = 10;
        moveToEnd(head, key);

        Console.Write("\nAfter moveToEnd(), the Linked list is\n");
        printList(head);
    }
}

// This code has been contributed by 29AjayKumar

// C# code to remove key
// element to end of linked list
using System;

// Node class
public class Node {
    public int data;
    public Node next;

    public Node(int data)
    {
        this.data = data;
        this.next = null;
    }
}

class GFG {

    static Node root;

    // Function to remove key to end
    public static Node keyToEnd(Node head, int key)
    {

        // Node to keep pointing to tail
        Node tail = head;

        if (head == null) {
            return null;
        }

        while (tail.next != null) {
            tail = tail.next;
        }

        // Node to point to last of linked list
        Node last = tail;

        Node current = head;
        Node prev = null;

        // Node prev2 to point to
        // previous when head.data!=key
        Node prev2 = null;

        // loop to perform operations
        // to remove key to end
        while (current != tail) {
            if (current.data == key && prev2 == null) {
                prev = current;
                current = current.next;
                head = current;
                last.next = prev;
                last = last.next;
                last.next = null;
                prev = null;
            }
            else {
                if (current.data == key && prev2 != null) {
                    prev = current;
                    current = current.next;
                    prev2.next = current;
                    last.next = prev;
                    last = last.next;
                    last.next = null;
                }
                else if (current != tail) {
                    prev2 = current;
                    current = current.next;
                }
            }
        }
        return head;
    }

    // Function to display linked list
    public static void display(Node root)
    {
        while (root != null) {
            Console.Write(root.data + " ");
            root = root.next;
        }
    }

    // Driver Code
    public static void Main()
    {
        root = new Node(5);
        root.next = new Node(2);
        root.next.next = new Node(2);
        root.next.next.next = new Node(7);
        root.next.next.next.next = new Node(2);
        root.next.next.next.next.next = new Node(2);
        root.next.next.next.next.next.next = new Node(2);

        int key = 2;
        Console.WriteLine("Linked List before operations :");
        display(root);
        Console.WriteLine("\nLinked List after operations :");
        root = keyToEnd(root, key);
        display(root);
    }
}

// This code is contributed by PrinciRaj1992