Insertion in linked list Java (#1694)

* Create InsertionInLinkedList.java

For Issue #513

* Update readme.md

Co-authored-by: Tarun Yadav <[email protected]>

Code/Java/InsertionInLinkedList.java

@@ -0,0 +1,181 @@
+/*
+ * To insert a node in a LinkedList.
+ * There are 2 cases:
+ * 1. To insert a node at the start of the linked list.
+ * 2. To insert a node in between the linked list.
+ */
+
+import java.util.*;
+
+class InsertionInLinkedList
+{
+    Node start;
+
+    InsertionInLinkedList()
+    {
+        start = null;
+    }
+
+    void create(Node node) 
+    {
+        //This function is to create the LinkedList
+        if (start == null)
+        {
+            start = node;
+        }
+        else 
+        {
+            Node temp = start;
+            while (temp.address != null)
+                temp = temp.address;
+            temp.address = node;
+        }
+    }
+
+    void display()
+    {
+        //This function is to display the linkedlist
+        Node temp = start;
+        System.out.println("Linked List: ");
+        while (temp!= null)
+        {
+            System.out.print(temp.data + " ");
+            temp = temp.address;
+        } 
+        System.out.println();
+    }
+
+    void insert(int pos, int value)
+    {
+        //This function is to insert a node in the linkedlist
+        Node ptr = null;
+
+        int ctr = 1;
+
+        if(pos == 1)
+        {
+            Node temp = new Node(value);
+            temp.data = value;
+            temp.address = start;
+            start = temp;
+        }
+
+        for(ptr = start; ptr != null; ptr = ptr.address)
+        {
+            ctr++;
+
+            if(ctr == pos)
+            {
+                Node temp = new Node(value);
+                temp.data = value;
+                temp.address = ptr.address;
+                ptr.address = temp;
+            }
+        }
+    }
+
+    public static void main()
+    {
+        Scanner scanner = new Scanner(System.in);
+
+        InsertionInLinkedList ob = new InsertionInLinkedList();
+
+        int data, flag=1, value, pos;
+        while(flag!=0)
+        {
+            System.out.println("Enter data in linked list: ");
+            data = scanner.nextInt(); scanner.nextLine();
+            ob.create(new Node(data));
+
+            System.out.println("Do you wish to continue? Enter 1 for yes and 0 for no: ");
+            flag = scanner.nextInt(); scanner.nextLine();
+        }
+        ob.display();
+
+        System.out.println("Enter value to be inserted in the linked list: ");
+        value = scanner.nextInt(); scanner.nextLine();
+        System.out.println("Enter position of insertion in the linked list: ");
+        pos = scanner.nextInt(); scanner.nextLine();
+
+        ob.insert(pos, value);
+        ob.display();
+    }
+}
+class Node
+{
+    public int data;
+    public Node address;
+    Node(int d) 
+    {
+        data = d;
+        address = null;
+    }
+}   
+
+/*
+  Test Cases-
+  
+  1.
+  Enter data in linked list: 
+  1
+  Do you wish to continue? Enter 1 for yes and 0 for no: 
+  1
+  Enter data in linked list: 
+  2
+  Do you wish to continue? Enter 1 for yes and 0 for no: 
+  1
+  Enter data in linked list: 
+  3
+  Do you wish to continue? Enter 1 for yes and 0 for no: 
+  1
+  Enter data in linked list: 
+  4
+  Do you wish to continue? Enter 1 for yes and 0 for no: 
+  1
+  Enter data in linked list: 
+  5
+  Do you wish to continue? Enter 1 for yes and 0 for no: 
+  0
+  Linked List: 
+  1 2 3 4 5 
+  Enter value to be inserted in the linked list: 
+  6
+  Enter position of insertion in the linked list: 
+  3
+  Linked List: 
+  1 2 6 3 4 5 
+  
+  2.
+  Enter data in linked list: 
+  1
+  Do you wish to continue? Enter 1 for yes and 0 for no: 
+  1
+  Enter data in linked list: 
+  2
+  Do you wish to continue? Enter 1 for yes and 0 for no: 
+  1
+  Enter data in linked list: 
+  3
+  Do you wish to continue? Enter 1 for yes and 0 for no: 
+  1
+  Enter data in linked list: 
+  4
+  Do you wish to continue? Enter 1 for yes and 0 for no: 
+  1
+  Enter data in linked list: 
+  5
+  Do you wish to continue? Enter 1 for yes and 0 for no: 
+  0
+  Linked List: 
+  1 2 3 4 5 
+  Enter value to be inserted in the linked list: 
+  7
+  Enter position of insertion in the linked list: 
+  1
+  Linked List: 
+  7 1 2 3 4 5 
+  
+  Time Complexity: O(n)
+  Space Complexity: O(n)
+  where n is the number of elements in the linked list
+ */

Linked_list/readme.md

@@ -31,19 +31,15 @@ properties.
 
 * Alternate Node Deletion ----> [C++](/Code/C++/Deletion of Alternate nodes in a linked list.cpp)
 * Cycle detection using Hare and Tortoise algorithm ----> [C++](/Code/C++/CycleDetectLinkedList.cpp) | [Java](/Code/Java/Cycle_Detection_In_Linked_List.java)
+* Insertion ----> [C++](/Code/C++/insertion_in_linked_list.cpp) | [Java](/Code/Java/InsertionInLinkedList.java)
+* Splitting ----> [C++](/Code/C++/Splitting_Linked_lists.cpp)
 * Deleting Node from Linked List ----> [Java](/Code/Java/DeleteNodeFromLinkedList.java)
 * Delete a given node without using head pointer ----> [C++](/Code/C++/delete_without_head.cpp)
-* Finding intersection node of two linked lists connected in y shape -----> [C++](Code/C++/Intersection_point_of_linked_list.cpp)
-* Finding Intersection of Linked Lists ----> [Python](/Code/Python/linked_lists_intersection.py)
+* Finding intersection node of two linked lists connected in y shape -----> [C++](Code/C++/Intersection_point_of_linked_list.cpp) | [Python](/Code/Python/linked_lists_intersection.py)
 * Implementation of Linked List ----> [Python](/Code/Python/linked_list.py)
-* Insertion ----> [C++](/Code/C++/insertion_in_linked_list.cpp)
-* Ispalindrome ----> [Python](/Code/Python/isPalindrome_linked_list.py)
 * Middle Element ----> [Python](/Code/Python/middle_element_linked_list.py)
-* Palindrome Check---->[C++](/Linked_list/PalindromeCheck.cpp) | [Java](/Linked_list/palindrome_checker.java)
+* Palindrome Check---->[C++](/Linked_list/PalindromeCheck.cpp) | [Java](/Linked_list/palindrome_checker.java) | [Python](/Code/Python/isPalindrome_linked_list.py)
 * Remove Duplicates from Unsorted List ----> [C++](/Code/C++/remove_duplicates.cpp)
 * Reversing a Linked List ----> [C++](/Code/C++/reverse_a_linked_list.cpp)
-* Remove Loop From Linked List C++(Linked_List/RemoveLoopFromLinkedList.cpp)
 * Reverse Linked List in groups of size k ---->[Python](/Code/Python/reverse_linkedlist_in_group_of_size_k.py)
-* Reversing a Linked List ----> [C++](/Code/C++/reverse_a_linked_list.cpp)
-* Splitting ----> [C++](/Code/C++/Splitting_Linked_lists.cpp)
 * Unrolled Linked List Implementation ----> [C++](/Code/C++/unrolled_linked_list.cpp)