# Sum of all distinct nodes in a linked list

Given a linked list and it may consist of duplicate nodes. The task is to find the sum of non-duplicate nodes.

Examples:

Input: 1 -> 2 -> 1 -> 3 -> 4 -> 3 -> NULL
Output: 6
2 and 4 are the only non-duplicate nodes and 2 + 4 = 6.

Input: 1 -> 3 -> 1 -> 3 -> 1 -> 3 -> NULL
Output: 0

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

Approach: We traverse the whole linked list and for each node we check throughout the linked list whether the node has duplicate or not. If there is no duplicate node then we add that node to the variable which stores the sum.

Below is the implementation of the above approach:

## C++

 `// C++ implementaion of the approach ` `#include ` `using` `namespace` `std; ` ` `  `// Represents a node of linked list ` `struct` `Node { ` `    ``int` `data; ` `    ``Node* next; ` `}; ` ` `  `// Function to insert node in a linked list ` `void` `insert(Node** head, ``int` `item) ` `{ ` `    ``Node* ptr = *head; ` `    ``Node* temp = ``new` `Node; ` ` `  `    ``temp->data = item; ` `    ``temp->next = NULL; ` ` `  `    ``if` `(*head == NULL) ` `        ``*head = temp; ` `    ``else` `{ ` `        ``while` `(ptr->next != NULL) ` `            ``ptr = ptr->next; ` `        ``ptr->next = temp; ` `    ``} ` `} ` ` `  `// Function to find the sum of non duplicate nodes ` `int` `sumOfNonDupNode(Node* head) ` `{ ` `    ``Node* ptr1 = head; ` `    ``Node* ptr2; ` `    ``int` `sum = 0, flag = 0; ` ` `  `    ``while` `(ptr1 != NULL) { ` `        ``ptr2 = head; ` `        ``bool` `flag = ``false``; ` ` `  `        ``// Check if current node has some duplicate ` `        ``while` `(ptr2 != NULL) { ` ` `  `            ``// Check for duplicate node ` `            ``if` `(ptr1 != ptr2 && ptr1->data == ptr2->data) { ` `                ``flag = ``true``; ` `                ``break``; ` `            ``} ` ` `  `            ``// Get to the next node ` `            ``ptr2 = ptr2->next; ` `        ``} ` ` `  `        ``// If current node is unique ` `        ``if` `(!flag) ` `            ``sum += ptr1->data; ` ` `  `        ``// Get to the next node ` `        ``ptr1 = ptr1->next; ` `    ``} ` `    ``return` `sum; ` `} ` ` `  `// Driver code ` `int` `main() ` `{ ` `    ``Node* head = NULL; ` ` `  `    ``insert(&head, 1); ` `    ``insert(&head, 2); ` `    ``insert(&head, 1); ` `    ``insert(&head, 3); ` `    ``insert(&head, 4); ` `    ``insert(&head, 3); ` ` `  `    ``cout << sumOfNonDupNode(head) << endl; ` ` `  `    ``return` `0; ` `} `

## Java

 `// Java implementaion of the approach ` `class` `GFG { ` ` `  `    ``// Represents a node of linked list ` `    ``static` `class` `Node { ` `        ``int` `data; ` `        ``Node next; ` `    ``} ` ` `  `    ``// Function to insert node in a linked list ` `    ``static` `Node insert(Node head, ``int` `item) ` `    ``{ ` `        ``Node ptr = head; ` `        ``Node temp = ``new` `Node(); ` ` `  `        ``temp.data = item; ` `        ``temp.next = ``null``; ` ` `  `        ``if` `(head == ``null``) ` `            ``head = temp; ` `        ``else` `{ ` `            ``while` `(ptr.next != ``null``) ` `                ``ptr = ptr.next; ` `            ``ptr.next = temp; ` `        ``} ` `        ``return` `head; ` `    ``} ` ` `  `    ``// Function to find the sum of non duplicate nodes ` `    ``static` `int` `sumOfNonDupNode(Node head) ` `    ``{ ` `        ``Node ptr1 = head; ` `        ``Node ptr2; ` `        ``int` `sum = ``0``; ` ` `  `        ``while` `(ptr1 != ``null``) { ` `            ``ptr2 = head; ` `            ``boolean` `flag = ``false``; ` ` `  `            ``// Check if current node has some duplicate ` `            ``while` `(ptr2 != ``null``) { ` ` `  `                ``// Check for duplicate node ` `                ``if` `(ptr1 != ptr2 && ptr1.data == ptr2.data) { ` `                    ``flag = ``true``; ` `                    ``break``; ` `                ``} ` ` `  `                ``// Get to the next node ` `                ``ptr2 = ptr2.next; ` `            ``} ` ` `  `            ``// If current node is unique ` `            ``if` `(!flag) ` `                ``sum += ptr1.data; ` ` `  `            ``// Get to the next node ` `            ``ptr1 = ptr1.next; ` `        ``} ` `        ``return` `sum; ` `    ``} ` ` `  `    ``// Driver code ` `    ``public` `static` `void` `main(String args[]) ` `    ``{ ` `        ``Node head = ``null``; ` ` `  `        ``head = insert(head, ``1``); ` `        ``head = insert(head, ``2``); ` `        ``head = insert(head, ``1``); ` `        ``head = insert(head, ``3``); ` `        ``head = insert(head, ``4``); ` `        ``head = insert(head, ``3``); ` ` `  `        ``System.out.print(sumOfNonDupNode(head)); ` `    ``} ` `} ` ` `  `// This code is contributed by Arnab Kundu `

## Python3

 `# Python3 implementation of the approach ` ` `  `# Represents node of the linked list ` `class` `Node: ` `     `  `    ``def` `__init__(``self``, data): ` `        ``self``.data ``=` `data ` `        ``self``.``next` `=` `None` ` `  `# Insertion in linked list ` `def` `insert(head, item): ` ` `  `    ``ptr ``=` `head ` `    ``temp ``=` `Node(item) ` `     `  `    ``if` `head ``=``=` `None``: ` `        ``head ``=` `temp ` `    ``else``: ` `        ``while` `ptr.``next` `!``=` `None``: ` `            ``ptr ``=` `ptr.``next` ` `  `        ``ptr.``next` `=` `temp ` `         `  `    ``return` `head ` ` `  `# Function to find the sum of  ` `# non duplicate nodes ` `def` `sumOfNonDupNode(head): ` ` `  `    ``ptr1 ``=` `head ` `    ``Sum` `=` `flag ``=` `0` ` `  `    ``while` `ptr1 !``=` `None``: ` `        ``ptr2, flag ``=` `head, ``False` ` `  `        ``# Check if current node  ` `        ``# has some duplicate ` `        ``while` `ptr2 !``=` `None``: ` ` `  `            ``# Check for duplicate node ` `            ``if` `(ptr1 !``=` `ptr2 ``and`  `                ``ptr1.data ``=``=` `ptr2.data):  ` `                ``flag ``=` `True` `                ``break` ` `  `            ``# Get to the next node ` `            ``ptr2 ``=` `ptr2.``next` `         `  `        ``# If current node is unique ` `        ``if` `not` `flag: ` `            ``Sum` `+``=` `ptr1.data ` ` `  `        ``# Get to the next node ` `        ``ptr1 ``=` `ptr1.``next` `     `  `    ``return` `Sum` ` `  `# Driver code ` `if` `__name__ ``=``=` `"__main__"``: ` ` `  `    ``head ``=` `None` ` `  `    ``head ``=` `insert(head, ``1``) ` `    ``head ``=` `insert(head, ``2``) ` `    ``head ``=` `insert(head, ``1``) ` `    ``head ``=` `insert(head, ``3``) ` `    ``head ``=` `insert(head, ``4``) ` `    ``head ``=` `insert(head, ``3``) ` ` `  `    ``print``(sumOfNonDupNode(head)) ` `     `  `# This code is contributed by Rituraj Jain `

## C#

 `// C# implementation of the approach ` `using` `System; ` ` `  `class` `GFG { ` ` `  `    ``public` `class` `Node { ` `        ``public` `int` `data; ` `        ``public` `Node next; ` `    ``} ` ` `  `    ``// Function to insert node in a linked list ` `    ``static` `Node insert(Node head, ``int` `item) ` `    ``{ ` `        ``Node ptr = head; ` `        ``Node temp = ``new` `Node(); ` ` `  `        ``temp.data = item; ` `        ``temp.next = ``null``; ` ` `  `        ``if` `(head == ``null``) ` `            ``head = temp; ` `        ``else` `{ ` `            ``while` `(ptr.next != ``null``) ` `                ``ptr = ptr.next; ` `            ``ptr.next = temp; ` `        ``} ` `        ``return` `head; ` `    ``} ` ` `  `    ``// Function to find the sum of non duplicate nodes ` `    ``static` `int` `sumOfNonDupNode(Node head) ` `    ``{ ` `        ``Node ptr1 = head; ` `        ``Node ptr2; ` `        ``int` `sum = 0; ` ` `  `        ``while` `(ptr1 != ``null``) { ` `            ``ptr2 = head; ` `            ``bool` `flag = ``false``; ` ` `  `            ``// Check if current node has some duplicate ` `            ``while` `(ptr2 != ``null``) { ` ` `  `                ``// Check for duplicate node ` `                ``if` `(ptr1 != ptr2 && ptr1.data == ptr2.data) { ` `                    ``flag = ``true``; ` `                    ``break``; ` `                ``} ` ` `  `                ``// Get to the next node ` `                ``ptr2 = ptr2.next; ` `            ``} ` ` `  `            ``// If current node is unique ` `            ``if` `(!flag) ` `                ``sum += ptr1.data; ` ` `  `            ``// Get to the next node ` `            ``ptr1 = ptr1.next; ` `        ``} ` `        ``return` `sum; ` `    ``} ` ` `  `    ``// Driver code ` `    ``public` `static` `void` `Main(String[] args) ` `    ``{ ` `        ``Node head = ``null``; ` ` `  `        ``head = insert(head, 1); ` `        ``head = insert(head, 2); ` `        ``head = insert(head, 1); ` `        ``head = insert(head, 3); ` `        ``head = insert(head, 4); ` `        ``head = insert(head, 3); ` ` `  `        ``Console.Write(sumOfNonDupNode(head)); ` `    ``} ` `} ` ` `  `// This code contributed by Rajput-Ji `

Output:

```6
```

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