# Sum and Product of all the nodes which are less than K in the linked list

Given a Linked List and a key K. The task is to calculate the sum and product all the nodes from the list that are lesser than the key K.

Examples:

Input: 12 -> 15 -> 9 -> 11 -> 5 -> 6, K = 9
Output: Sum = 11, Product = 30

Input: 13 -> 4 -> 16 -> 9 -> 22 -> 45 -> 5 -> 16 -> 6, K = 10
Output: Sum = 24, Product = 1080

## Recommended: Please try your approach on {IDE} first, before moving on to the solution.

Approach: Start traversing from the head and check if current node’s value is less than K. If yes, then add that node to the sum and multiply that node for the product and move forward in the list.

Below is the implementation of the above approach:

## C++

 `// C++ program to sum and product all the ` `// nodes from the list that are lesser ` `// than the specified value K ` `#include ` `using` `namespace` `std; ` ` `  `// structure of a node ` `struct` `Node { ` `    ``int` `data; ` `    ``Node* next; ` `}; ` ` `  `// function to get a new node ` `Node* getNode(``int` `data) ` `{ ` `    ``Node* newNode = ``new` `Node; ` `    ``newNode->data = data; ` `    ``newNode->next = NULL; ` `    ``return` `newNode; ` `} ` ` `  `// function to sum all the nodes from the list ` `// that are lesser than the specified value K ` `int` `sumLesserNodes(Node** head_ref, ``int` `K) ` `{ ` `    ``Node* temp = *head_ref; ` ` `  `    ``int` `sum = 0; ` `    ``while` `(temp != NULL) { ` `        ``if` `(temp->data < K) ` `            ``sum += temp->data; ` `        ``temp = temp->next; ` `    ``} ` ` `  `    ``return` `sum; ` `} ` ` `  `// function to product all the nodes from the list ` `// that are lesser than the specified value K ` `int` `productLesserNodes(Node** head_ref, ``int` `K) ` `{ ` `    ``Node* temp = *head_ref; ` ` `  `    ``int` `product = 1; ` `    ``while` `(temp != NULL) { ` `        ``if` `(temp->data < K) ` `            ``product *= temp->data; ` `        ``temp = temp->next; ` `    ``} ` ` `  `    ``return` `product; ` `} ` ` `  `// Driver code ` `int` `main() ` `{ ` `    ``// Create list: 12->15->9->11->5->6 ` `    ``Node* head = getNode(12); ` `    ``head->next = getNode(15); ` `    ``head->next->next = getNode(9); ` `    ``head->next->next->next = getNode(11); ` `    ``head->next->next->next->next = getNode(5); ` `    ``head->next->next->next->next->next = getNode(6); ` ` `  `    ``int` `K = 9; ` `    ``cout << ``"Sum = "` `<< sumLesserNodes(&head, K) << endl; ` `    ``cout << ``"Product = "` `<< productLesserNodes(&head, K) << endl; ` ` `  `    ``return` `0; ` `} `

## Java

 `// Java program to sum and product all the ` `// nodes from the list that are lesser ` `// than the specified value K ` `class` `GFG  ` `{ ` ` `  `// structure of a node ` `static` `class` `Node  ` `{ ` `    ``int` `data; ` `    ``Node next; ` `}; ` ` `  `// function to get a new node ` `static` `Node getNode(``int` `data) ` `{ ` `    ``Node newNode = ``new` `Node(); ` `    ``newNode.data = data; ` `    ``newNode.next = ``null``; ` `    ``return` `newNode; ` `} ` ` `  `// function to sum all the nodes from the list ` `// that are lesser than the specified value K ` `static` `int` `sumLesserNodes(Node head_ref, ``int` `K) ` `{ ` `    ``Node temp = head_ref; ` ` `  `    ``int` `sum = ``0``; ` `    ``while` `(temp != ``null``)  ` `    ``{ ` `        ``if` `(temp.data < K) ` `            ``sum += temp.data; ` `        ``temp = temp.next; ` `    ``} ` ` `  `    ``return` `sum; ` `} ` ` `  `// function to product all the nodes from the list ` `// that are lesser than the specified value K ` `static` `int` `productLesserNodes(Node head_ref, ``int` `K) ` `{ ` `    ``Node temp = head_ref; ` ` `  `    ``int` `product = ``1``; ` `    ``while` `(temp != ``null``)  ` `    ``{ ` `        ``if` `(temp.data < K) ` `            ``product *= temp.data; ` `        ``temp = temp.next; ` `    ``} ` ` `  `    ``return` `product; ` `} ` ` `  `// Driver code ` `public` `static` `void` `main(String[] args)  ` `{ ` ` `  `    ``// Create list: 12->15->9->11->5->6 ` `    ``Node head = getNode(``12``); ` `    ``head.next = getNode(``15``); ` `    ``head.next.next = getNode(``9``); ` `    ``head.next.next.next = getNode(``11``); ` `    ``head.next.next.next.next = getNode(``5``); ` `    ``head.next.next.next.next.next = getNode(``6``); ` ` `  `    ``int` `K = ``9``; ` `    ``System.out.println(``"Sum = "` `+ sumLesserNodes(head, K)); ` `    ``System.out.println(``"Product = "` `+ productLesserNodes(head, K)); ` `} ` `} ` ` `  `// This code has been contributed by 29AjayKumar `

## Python3

 `# Python3 program to sum and product all the ` `# nodes from the list that are lesser ` `# than the specified value K ` ` `  `# Node of the single linked list  ` `class` `Node:  ` `     `  `    ``def` `__init__(``self``, data):  ` `        ``self``.data ``=` `data  ` `        ``self``.``next` `=` `None` ` `  `# function to get a new node ` `def` `getNode(data): ` ` `  `    ``newNode ``=` `Node(``0``) ` `    ``newNode.data ``=` `data ` `    ``newNode.``next` `=` `None` `    ``return` `newNode ` ` `  `# function to sum all the nodes from the list ` `# that are lesser than the specified value K ` `def` `sumLesserNodes(head_ref, K): ` ` `  `    ``temp ``=` `head_ref ` ` `  `    ``sum` `=` `0` `    ``while` `(temp !``=` `None``) : ` `        ``if` `(temp.data < K): ` `            ``sum` `+``=` `temp.data ` `        ``temp ``=` `temp.``next` `     `  `    ``return` `sum` ` `  `# function to product all the nodes from the list ` `# that are lesser than the specified value K ` `def` `productLesserNodes(head_ref,K): ` ` `  `    ``temp ``=` `head_ref ` ` `  `    ``product ``=` `1` `    ``while` `(temp !``=` `None``) : ` `        ``if` `(temp.data < K): ` `            ``product ``*``=` `temp.data ` `        ``temp ``=` `temp.``next` `     `  `    ``return` `product ` ` `  `# Driver Code ` `if` `__name__ ``=``=` `"__main__"``:  ` ` `  `    ``# Create list: 12.15.9.11.5.6 ` `    ``head ``=` `getNode(``12``) ` `    ``head.``next` `=` `getNode(``15``) ` `    ``head.``next``.``next` `=` `getNode(``9``) ` `    ``head.``next``.``next``.``next` `=` `getNode(``11``) ` `    ``head.``next``.``next``.``next``.``next` `=` `getNode(``5``) ` `    ``head.``next``.``next``.``next``.``next``.``next` `=` `getNode(``6``) ` ` `  `    ``K ``=` `9` `    ``print``(``"Sum ="``, sumLesserNodes(head, K)) ` `    ``print``(``"Product ="``, productLesserNodes(head, K)) ` ` `  `# This code is contributed by Arnab Kundu `

## C#

 `// C# program to sum and product all the ` `// nodes from the list that are lesser ` `// than the specified value K ` `using` `System; ` `     `  `class` `GFG  ` `{ ` ` `  `// structure of a node ` `public` `class` `Node  ` `{ ` `    ``public` `int` `data; ` `    ``public` `Node next; ` `}; ` ` `  `// function to get a new node ` `static` `Node getNode(``int` `data) ` `{ ` `    ``Node newNode = ``new` `Node(); ` `    ``newNode.data = data; ` `    ``newNode.next = ``null``; ` `    ``return` `newNode; ` `} ` ` `  `// function to sum all the nodes from the list ` `// that are lesser than the specified value K ` `static` `int` `sumLesserNodes(Node head_ref, ``int` `K) ` `{ ` `    ``Node temp = head_ref; ` ` `  `    ``int` `sum = 0; ` `    ``while` `(temp != ``null``)  ` `    ``{ ` `        ``if` `(temp.data < K) ` `            ``sum += temp.data; ` `        ``temp = temp.next; ` `    ``} ` ` `  `    ``return` `sum; ` `} ` ` `  `// function to product all the nodes from the list ` `// that are lesser than the specified value K ` `static` `int` `productLesserNodes(Node head_ref, ``int` `K) ` `{ ` `    ``Node temp = head_ref; ` ` `  `    ``int` `product = 1; ` `    ``while` `(temp != ``null``)  ` `    ``{ ` `        ``if` `(temp.data < K) ` `            ``product *= temp.data; ` `        ``temp = temp.next; ` `    ``} ` ` `  `    ``return` `product; ` `} ` ` `  `// Driver code ` `public` `static` `void` `Main(String[] args)  ` `{ ` ` `  `    ``// Create list: 12->15->9->11->5->6 ` `    ``Node head = getNode(12); ` `    ``head.next = getNode(15); ` `    ``head.next.next = getNode(9); ` `    ``head.next.next.next = getNode(11); ` `    ``head.next.next.next.next = getNode(5); ` `    ``head.next.next.next.next.next = getNode(6); ` ` `  `    ``int` `K = 9; ` `    ``Console.WriteLine(``"Sum = "` `+ sumLesserNodes(head, K)); ` `    ``Console.WriteLine(``"Product = "` `+ productLesserNodes(head, K)); ` `} ` `} ` ` `  `// This code contributed by Rajput-Ji `

Output:

```Sum = 11
Product = 30
```

Time Complexity: O(N)

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