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# Create new linked list from two given linked list with greater element at each node

Given two linked list of the same size, the task is to create a new linked list using those linked lists. The condition is that the greater node among both linked list will be added to the new linked list.
Examples:

```Input:  list1 = 5->2->3->8
list2 = 1->7->4->5
Output:  New list = 5->7->4->8

Input: list1 = 2->8->9->3
list2 = 5->3->6->4
Output:  New list = 5->8->9->4```

Approach: We traverse both the linked list at the same time and compare node of both lists. The node which is greater among them will be added to the new linked list. We do this for each node.

## C++

 `// C++ program to create a new linked list``// from two given linked list``// of the same size with``// the greater element among the two at each node` `#include ``using` `namespace` `std;` `// Representation of node``struct` `Node {``    ``int` `data;``    ``Node* next;``};` `// Function to insert node in a linked list``void` `insert(Node** root, ``int` `item)``{``    ``Node *ptr, *temp;``    ``temp = ``new` `Node;``    ``temp->data = item;``    ``temp->next = NULL;` `    ``if` `(*root == NULL)``        ``*root = temp;``    ``else` `{``        ``ptr = *root;``        ``while` `(ptr->next != NULL)``            ``ptr = ptr->next;` `        ``ptr->next = temp;``    ``}``}` `// Function which returns new linked list``Node* newList(Node* root1, Node* root2)``{``    ``Node *ptr1 = root1, *ptr2 = root2, *ptr;``    ``Node *root = NULL, *temp;` `    ``while` `(ptr1 != NULL) {``        ``temp = ``new` `Node;``        ``temp->next = NULL;` `        ``// Compare for greater node``        ``if` `(ptr1->data < ptr2->data)``            ``temp->data = ptr2->data;``        ``else``            ``temp->data = ptr1->data;` `        ``if` `(root == NULL)``            ``root = temp;``        ``else` `{``            ``ptr = root;``            ``while` `(ptr->next != NULL)``                ``ptr = ptr->next;` `            ``ptr->next = temp;``        ``}``        ``ptr1 = ptr1->next;``        ``ptr2 = ptr2->next;``    ``}``    ``return` `root;``}` `void` `display(Node* root)``{``    ``while` `(root != NULL) {``        ``cout << root->data << ``"->"``;``        ``root = root->next;``    ``}` `    ``cout << endl;``}` `// Driver code``int` `main()``{``    ``Node *root1 = NULL, *root2 = NULL, *root = NULL;` `    ``// First linked list``    ``insert(&root1, 5);``    ``insert(&root1, 2);``    ``insert(&root1, 3);``    ``insert(&root1, 8);` `    ``cout << ``"First List:  "``;``    ``display(root1);` `    ``// Second linked list``    ``insert(&root2, 1);``    ``insert(&root2, 7);``    ``insert(&root2, 4);``    ``insert(&root2, 5);` `    ``cout << ``"Second List: "``;``    ``display(root2);` `    ``root = newList(root1, root2);``    ``cout << ``"New List:    "``;``    ``display(root);``    ``return` `0;``}`

## Java

 `// Java program to create a new linked list``// from two given linked list``// of the same size with``// the greater element among the two at each node``import` `java.util.*;` `class` `GFG``{` `// Representation of node``static` `class` `Node``{``    ``int` `data;``    ``Node next;``};` `// Function to insert node in a linked list``static` `Node insert(Node root, ``int` `item)``{``    ``Node ptr, temp;``    ``temp = ``new` `Node();``    ``temp.data = item;``    ``temp.next = ``null``;` `    ``if` `(root == ``null``)``        ``root = temp;``    ``else` `{``        ``ptr = root;``        ``while` `(ptr.next != ``null``)``            ``ptr = ptr.next;` `        ``ptr.next = temp;``    ``}``    ``return` `root;``}` `// Function which returns new linked list``static` `Node newList(Node root1, Node root2)``{``    ``Node ptr1 = root1, ptr2 = root2, ptr;``    ``Node root = ``null``, temp;` `    ``while` `(ptr1 != ``null``) {``        ``temp = ``new` `Node();``        ``temp.next = ``null``;` `        ``// Compare for greater node``        ``if` `(ptr1.data < ptr2.data)``            ``temp.data = ptr2.data;``        ``else``            ``temp.data = ptr1.data;` `        ``if` `(root == ``null``)``            ``root = temp;``        ``else` `{``            ``ptr = root;``            ``while` `(ptr.next != ``null``)``                ``ptr = ptr.next;` `            ``ptr.next = temp;``        ``}``        ``ptr1 = ptr1.next;``        ``ptr2 = ptr2.next;``    ``}``    ``return` `root;``}` `static` `void` `display(Node root)``{``    ``while` `(root != ``null``)``    ``{``        ``System.out.print( root.data + ``"->"``);``        ``root = root.next;``    ``}``    ``System.out.println();``}` `// Driver code``public` `static` `void` `main(String args[])``{``    ``Node root1 = ``null``, root2 = ``null``, root = ``null``;` `    ``// First linked list``    ``root1=insert(root1, ``5``);``    ``root1=insert(root1, ``2``);``    ``root1=insert(root1, ``3``);``    ``root1=insert(root1, ``8``);` `    ``System.out.print(``"First List: "``);``    ``display(root1);` `    ``// Second linked list``    ``root2=insert(root2, ``1``);``    ``root2=insert(root2, ``7``);``    ``root2=insert(root2, ``4``);``    ``root2=insert(root2, ``5``);` `    ``System.out.print( ``"Second List: "``);``    ``display(root2);` `    ``root = newList(root1, root2);``    ``System.out.print(``"New List: "``);``    ``display(root);``}``}` `// This code is contributed by Arnab Kundu`

## Python3

 `# Python3 program to create a``# new linked list from two given``# linked list of the same size with``# the greater element among the two``# at each node` `# Node class``class` `Node:` `    ``# Function to initialise the node object``    ``def` `__init__(``self``, data):``        ``self``.data ``=` `data``        ``self``.``next` `=` `None` `# Function to insert node in a linked list``def` `insert(root, item):` `    ``temp ``=` `Node(``0``)``    ``temp.data ``=` `item``    ``temp.``next` `=` `None` `    ``if` `(root ``=``=` `None``):``        ``root ``=` `temp``    ``else` `:``        ``ptr ``=` `root``        ``while` `(ptr.``next` `!``=` `None``):``            ``ptr ``=` `ptr.``next` `        ``ptr.``next` `=` `temp``        ` `    ``return` `root` `# Function which returns new linked list``def` `newList(root1, root2):` `    ``ptr1 ``=` `root1``    ``ptr2 ``=` `root2``    ` `    ``root ``=` `None``    ``while` `(ptr1 !``=` `None``) :``        ``temp ``=` `Node(``0``)``        ``temp.``next` `=` `None` `        ``# Compare for greater node``        ``if` `(ptr1.data < ptr2.data):``            ``temp.data ``=` `ptr2.data``        ``else``:``            ``temp.data ``=` `ptr1.data` `        ``if` `(root ``=``=` `None``):``            ``root ``=` `temp``        ``else` `:``            ``ptr ``=` `root``            ``while` `(ptr.``next` `!``=` `None``):``                ``ptr ``=` `ptr.``next` `            ``ptr.``next` `=` `temp``        ` `        ``ptr1 ``=` `ptr1.``next``        ``ptr2 ``=` `ptr2.``next``    ` `    ``return` `root` `def` `display(root):` `    ``while` `(root !``=` `None``) :``        ``print``(root.data, ``"->"``, end ``=` `" "``)``        ``root ``=` `root.``next``    ` `    ``print``(``" "``);` `# Driver Code``if` `__name__``=``=``'__main__'``:` `    ``root1 ``=` `None``    ``root2 ``=` `None``    ``root ``=` `None` `    ``# First linked list``    ``root1 ``=` `insert(root1, ``5``)``    ``root1 ``=` `insert(root1, ``2``)``    ``root1 ``=` `insert(root1, ``3``)``    ``root1 ``=` `insert(root1, ``8``)` `    ``print``(``"First List: "``, end ``=` `" "``)``    ``display(root1)` `    ``# Second linked list``    ``root2 ``=` `insert(root2, ``1``)``    ``root2 ``=` `insert(root2, ``7``)``    ``root2 ``=` `insert(root2, ``4``)``    ``root2 ``=` `insert(root2, ``5``)` `    ``print``(``"Second List: "``, end ``=` `" "``)``    ``display(root2)` `    ``root ``=` `newList(root1, root2)``    ``print``(``"New List: "``, end ``=` `" "``)``    ``display(root)` `# This code is contributed by Arnab Kundu`

## C#

 `// C# program to create a new linked list``// from two given linked list``// of the same size with``// the greater element among the two at each node``using` `System;``    ` `class` `GFG``{` `// Representation of node``public` `class` `Node``{``    ``public` `int` `data;``    ``public` `Node next;``};` `// Function to insert node in a linked list``static` `Node insert(Node root, ``int` `item)``{``    ``Node ptr, temp;``    ``temp = ``new` `Node();``    ``temp.data = item;``    ``temp.next = ``null``;` `    ``if` `(root == ``null``)``        ``root = temp;``    ``else``    ``{``        ``ptr = root;``        ``while` `(ptr.next != ``null``)``            ``ptr = ptr.next;` `        ``ptr.next = temp;``    ``}``    ``return` `root;``}` `// Function which returns new linked list``static` `Node newList(Node root1, Node root2)``{``    ``Node ptr1 = root1, ptr2 = root2, ptr;``    ``Node root = ``null``, temp;` `    ``while` `(ptr1 != ``null``)``    ``{``        ``temp = ``new` `Node();``        ``temp.next = ``null``;` `        ``// Compare for greater node``        ``if` `(ptr1.data < ptr2.data)``            ``temp.data = ptr2.data;``        ``else``            ``temp.data = ptr1.data;` `        ``if` `(root == ``null``)``            ``root = temp;``        ``else``        ``{``            ``ptr = root;``            ``while` `(ptr.next != ``null``)``                ``ptr = ptr.next;` `            ``ptr.next = temp;``        ``}``        ``ptr1 = ptr1.next;``        ``ptr2 = ptr2.next;``    ``}``    ``return` `root;``}` `static` `void` `display(Node root)``{``    ``while` `(root != ``null``)``    ``{``        ``Console.Write( root.data + ``"->"``);``        ``root = root.next;``    ``}``    ``Console.WriteLine();``}` `// Driver code``public` `static` `void` `Main(String []args)``{``    ``Node root1 = ``null``, root2 = ``null``, root = ``null``;` `    ``// First linked list``    ``root1 = insert(root1, 5);``    ``root1 = insert(root1, 2);``    ``root1 = insert(root1, 3);``    ``root1 = insert(root1, 8);` `    ``Console.Write(``"First List: "``);``    ``display(root1);` `    ``// Second linked list``    ``root2 = insert(root2, 1);``    ``root2 = insert(root2, 7);``    ``root2 = insert(root2, 4);``    ``root2 = insert(root2, 5);` `    ``Console.Write( ``"Second List: "``);``    ``display(root2);` `    ``root = newList(root1, root2);``    ``Console.Write(``"New List: "``);``    ``display(root);``}``}` `// This code has been contributed by 29AjayKumar`

## Javascript

 ``

Output:

```First List:  5->2->3->8->
Second List: 1->7->4->5->
New List:    5->7->4->8->```

Time complexity: O(n) where n is size of linked list

Space complexity: O(1) since using constant space

My Personal Notes arrow_drop_up