# Find modular node in a linked list

Given a singly linked list and a number k, find the last node whose n%k == 0, where n is the number of nodes in the list.

Examples:

```Input : list = 1->2->3->4->5->6->7
k = 3
Output : 6

Input : list = 3->7->1->9->8
k = 2
Output : 9```
1. Take a pointer modularNode and initialize it with NULL. Traverse the linked list.
2.  For every i%k=0, update modularNode.

Implementation:

## C++

 `// C++ program to find modular node in a linked list` `#include `   `/* Linked list node */` `struct` `Node {` `    ``int` `data;` `    ``Node* next;` `};`   `/* Function to create a new node with given data */` `Node* newNode(``int` `data)` `{` `    ``Node* new_node = ``new` `Node;` `    ``new_node->data = data;` `    ``new_node->next = NULL;` `    ``return` `new_node;` `}`   `/* Function to find modular node in the linked list */` `Node* modularNode(Node* head, ``int` `k)` `{` `    ``// Corner cases` `    ``if` `(k <= 0 || head == NULL)` `        ``return` `NULL;   `   `    ``// Traverse the given list` `    ``int` `i = 1;` `    ``Node* modularNode = NULL;` `    ``for` `(Node* temp = head; temp != NULL; temp = temp->next) {` `        ``if` `(i % k == 0) ` `            ``modularNode = temp;` `        `  `        ``i++;` `    ``}` `    ``return` `modularNode;` `}`   `/* Driver program to test above function */` `int` `main(``void``)` `{` `    ``Node* head = newNode(1);` `    ``head->next = newNode(2);` `    ``head->next->next = newNode(3);` `    ``head->next->next->next = newNode(4);` `    ``head->next->next->next->next = newNode(5);` `    ``int` `k = 2;` `    ``Node* answer = modularNode(head, k);` `    ``printf``(``"\nModular node is "``);` `    ``if` `(answer != NULL) ` `        ``printf``(``"%d\n"``, answer->data);` `    ``else` `        ``printf``(``"null\n"``);` `    ``return` `0;` `}`

## Java

 `// A Java program to find modular node in a linked list` `public` `class` `GFG` `{` `    ``// A Linkedlist node` `    ``static` `class` `Node{` `        ``int` `data;` `        ``Node next;` `        ``Node(``int` `data){` `            ``this``.data = data;` `        ``}` `    ``}` `    `  `    ``// Function to find modular node in the linked list` `    ``static` `Node modularNode(Node head, ``int` `k)` `    ``{` `        ``// Corner cases` `        ``if` `(k <= ``0` `|| head == ``null``)` `            ``return` `null``;   ` `     `  `        ``// Traverse the given list` `        ``int` `i = ``1``;` `        ``Node modularNode = ``null``;` `        ``for` `(Node temp = head; temp != ``null``; temp = temp.next) {` `            ``if` `(i % k == ``0``) ` `                ``modularNode = temp;` `             `  `            ``i++;` `        ``}` `        ``return` `modularNode;` `    ``}` `    `  `    ``// Driver code to test above function` `    ``public` `static` `void` `main(String[] args) ` `    ``{` `        ``Node head = ``new` `Node(``1``);` `        ``head.next = ``new` `Node(``2``);` `        ``head.next.next = ``new` `Node(``3``);` `        ``head.next.next.next = ``new` `Node(``4``);` `        ``head.next.next.next.next = ``new` `Node(``5``);` `        ``int` `k = ``2``;` `        ``Node answer = modularNode(head, k);` `        ``System.out.print(``"Modular node is "``);` `        ``if` `(answer != ``null``) ` `            ``System.out.println(answer.data);` `        ``else` `            ``System.out.println(``"null"``);` `    ``}` `}` `// This code is contributed by Sumit Ghosh`

## Python3

 `# Python3 program to find modular node ` `# in a linked list` `import` `math`   `# Linked list node` `class` `Node:` `    ``def` `__init__(``self``, data):` `        ``self``.data ``=` `data` `        ``self``.``next` `=` `None`   `# Function to create a new node ` `# with given data` `def` `newNode(data):` `    ``new_node ``=` `Node(data)` `    ``new_node.data ``=` `data` `    ``new_node.``next` `=` `None` `    ``return` `new_node`   `# Function to find modular node ` `# in the linked list` `def` `modularNode(head, k):` `    `  `    ``# Corner cases` `    ``if` `(k <``=` `0` `or` `head ``=``=` `None``):` `        ``return` `None`   `    ``# Traverse the given list` `    ``i ``=` `1` `    ``modularNode ``=` `None` `    ``temp ``=` `head` `    ``while` `(temp !``=` `None``):` `        ``if` `(i ``%` `k ``=``=` `0``):` `            ``modularNode ``=` `temp`   `        ``i ``=` `i ``+` `1` `        ``temp ``=` `temp.``next` `    ``return` `modularNode`   `# Driver Code` `if` `__name__ ``=``=` `'__main__'``:` `    ``head ``=` `newNode(``1``)` `    ``head.``next` `=` `newNode(``2``)` `    ``head.``next``.``next` `=` `newNode(``3``)` `    ``head.``next``.``next``.``next` `=` `newNode(``4``)` `    ``head.``next``.``next``.``next``.``next` `=` `newNode(``5``)` `    ``k ``=` `2` `    ``answer ``=` `modularNode(head, k)` `    ``print``(``"Modular node is"``, end ``=` `' '``)` `    ``if` `(answer !``=` `None``):` `        ``print``(answer.data, end ``=` `' '``)` `    ``else``:` `        ``print``(``"None"``)`   `# This code is contributed by Srathore`

## C#

 `// C# program to find modular node in a linked list` `using` `System;`   `class` `GFG ` `{ ` `    ``// A Linkedlist node ` `    ``public` `class` `Node` `    ``{ ` `        ``public` `int` `data; ` `        ``public` `Node next; ` `        ``public` `Node(``int` `data)` `        ``{ ` `            ``this``.data = data; ` `        ``} ` `    ``} ` `    `  `    ``// Function to find modular node in the linked list ` `    ``static` `Node modularNode(Node head, ``int` `k) ` `    ``{ ` `        ``// Corner cases ` `        ``if` `(k <= 0 || head == ``null``) ` `            ``return` `null``; ` `    `  `        ``// Traverse the given list ` `        ``int` `i = 1; ` `        ``Node modularNode = ``null``; ` `        ``for` `(Node temp = head; temp != ``null``; temp = temp.next)` `        ``{ ` `            ``if` `(i % k == 0) ` `                ``modularNode = temp; ` `            `  `            ``i++; ` `        ``} ` `        ``return` `modularNode; ` `    ``} ` `    `  `    ``// Driver code  ` `    ``public` `static` `void` `Main(String[] args) ` `    ``{ ` `        ``Node head = ``new` `Node(1); ` `        ``head.next = ``new` `Node(2); ` `        ``head.next.next = ``new` `Node(3); ` `        ``head.next.next.next = ``new` `Node(4); ` `        ``head.next.next.next.next = ``new` `Node(5); ` `        ``int` `k = 2; `   `        ``Node answer = modularNode(head, k); ` `        ``Console.Write(``"Modular node is "``); `   `        ``if` `(answer != ``null``) ` `            ``Console.WriteLine(answer.data); ` `        ``else` `            ``Console.WriteLine(``"null"``); ` `    ``} ` `} `   `// This code is contributed by Rajput-JI`

## Javascript

 ``

Output

`Modular node is 4`

Complexity Analysis:

• Time Complexity: O(n).
• Space complexity: O(1).

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