Product of the alternate nodes of linked list Last Updated : 06 Sep, 2022 Comments Improve Suggest changes Like Article Like Report Given a linked list, the task is to print the product of alternate nodes of the given linked list. Examples: Input : 1 -> 8 -> 3 -> 10 -> 17 -> 22 -> 29 -> 42 Output : 1479 Alternate nodes : 1 -> 3 -> 17 -> 29 Input : 10 -> 17 -> 33 -> 38 -> 73 Output : 24090 Alternate nodes : 10 -> 33 -> 73 Iterative Approach: Traverse the whole linked list.Set prod = 1 and count=0.Multiply the data of the node with the prod when the count is even.Visit the next node. Below is the implementation of this approach: C++ // C++ code to print the product of Alternate Nodes #include <bits/stdc++.h> using namespace std; /* Link list node */ struct Node { int data; struct Node* next; }; /* Function to get the product of alternate nodes of the linked list */ int productAlternateNode(struct Node* head) { int count = 0; int prod = 1; while (head != NULL) { // when count is even product the data of node if (count % 2 == 0) prod *= head->data; // count the nodes count++; // move on the next node. head = head->next; } return prod; } // Function to push node at head void push(struct Node** head_ref, int new_data) { struct Node* new_node = new Node; new_node->data = new_data; new_node->next = (*head_ref); (*head_ref) = new_node; } // Driver code int main() { /* Start with the empty list */ struct Node* head = NULL; /* Use push() function to construct the below list 8 -> 23 -> 11 -> 29 -> 12 */ push(&head, 12); push(&head, 29); push(&head, 11); push(&head, 23); push(&head, 8); cout << productAlternateNode(head); return 0; } // This code is contributed by shivani singh C // C code to print the product of Alternate Nodes #include <stdio.h> #include <stdlib.h> /* Link list node */ struct Node { int data; struct Node* next; }; /* Function to get the product of alternate nodes of the linked list */ int productAlternateNode(struct Node* head) { int count = 0; int prod = 1; while (head != NULL) { // when count is even product the data of node if (count % 2 == 0) prod *= head->data; // count the nodes count++; // move on the next node. head = head->next; } return prod; } // Function to push node at head void push(struct Node** head_ref, int new_data) { struct Node* new_node = (struct Node*)malloc(sizeof(struct Node)); new_node->data = new_data; new_node->next = (*head_ref); (*head_ref) = new_node; } // Driver code int main() { /* Start with the empty list */ struct Node* head = NULL; /* Use push() function to construct the below list 8 -> 23 -> 11 -> 29 -> 12 */ push(&head, 12); push(&head, 29); push(&head, 11); push(&head, 23); push(&head, 8); printf(" %d ", productAlternateNode(head)); return 0; } Java // Java code to print the product of Alternate Nodes class GFG { /* Link list node */ static class Node { int data; Node next; }; /* Function to get the alternate nodes of the linked list */ static int productAlternateNode( Node head) { int count = 0; int product = 1; while (head != null) { // when count is even product the nodes if (count % 2 == 0) product *= head.data; // count the nodes count++; // move on the next node. head = head.next; } return product; } // Function to push node at head static Node push( Node head_ref, int new_data) { Node new_node =new Node(); new_node.data = new_data; new_node.next = (head_ref); (head_ref) = new_node; return head_ref; } // Driver code public static void main(String args[]) { /* Start with the empty list */ Node head = null; /* Use push() function to con the below list 8 . 23 . 11 . 29 . 12 */ head = push(head, 12); head = push(head, 29); head = push(head, 11); head = push(head, 23); head = push(head, 8); System.out.printf(" %d ", productAlternateNode(head)); } } // This code is contributed by Arnab Kundu Python3 # Python3 code to print the # product of Alternate Nodes import math # Link list node class Node: def __init__(self, data): self.data = data self.next = None # Function to get the product of alternate # nodes of the linked list def productAlternateNode(head): count = 0 prod = 1 while (head != None): # when count is even, product # the data of node if (count % 2 == 0): prod *= head.data # count the nodes count = count + 1 # move on the next node. head = head.next return prod # Function to head=push node at head def push(head_ref, new_data): new_node = Node(new_data) #new_node.data = new_data new_node.next = head_ref head_ref = new_node return head_ref # Driver code if __name__=='__main__': # Start with the empty list head = None # Use head=push() function to construct #the below list 8 . 23 . 11 . 29 . 12 head = push(head, 12) head = push(head, 29) head = push(head, 11) head = push(head, 23) head = push(head, 8) print(productAlternateNode(head)) # This code is contributed by Srathore C# // C# code to print the product of Alternate Nodes using System; class GFG { /* Link list node */ public class Node { public int data; public Node next; }; /* Function to get the alternate nodes of the linked list */ static int productAlternateNode( Node head) { int count = 0; int product = 1; while (head != null) { // when count is even product the nodes if (count % 2 == 0) product *= head.data; // count the nodes count++; // move on the next node. head = head.next; } return product; } // Function to push node at head static Node push( Node head_ref, int new_data) { Node new_node =new Node(); new_node.data = new_data; new_node.next = (head_ref); (head_ref) = new_node; return head_ref; } // Driver code public static void Main(String []args) { /* Start with the empty list */ Node head = null; /* Use push() function to con the below list 8 . 23 . 11 . 29 . 12 */ head = push(head, 12); head = push(head, 29); head = push(head, 11); head = push(head, 23); head = push(head, 8); Console.Write(" {0} ", productAlternateNode(head)); } } // This code has been contributed by 29AjayKumar JavaScript <script> // javascript code to print the product of Alternate Nodes /* Link list node */ class Node { constructor(val) { this.data = val; this.next = null; } } /* * Function to get the alternate nodes of the linked list */ function productAlternateNode(head) { var count = 0; var product = 1; while (head != null) { // when count is even product the nodes if (count % 2 == 0) product *= head.data; // count the nodes count++; // move on the next node. head = head.next; } return product; } // Function to push node at head function push(head_ref , new_data) { var new_node = new Node(); new_node.data = new_data; new_node.next = (head_ref); (head_ref) = new_node; return head_ref; } // Driver code /* Start with the empty list */ var head = null; /* * Use push() function to construct the below list 8 . 23 . 11 . 29 . 12 */ head = push(head, 12); head = push(head, 29); head = push(head, 11); head = push(head, 23); head = push(head, 8); document.write( productAlternateNode(head)); // This code contributed by Rajput-Ji </script> Output1056 Complexity Analysis: Time Complexity: O(N)Auxiliary Space: O(1) Recursive Approach: Initialize a static variable(say flag).If the flag is odd, multiply the node with the product.Increase head and flag by 1, and recurse for next nodes. Below is the implementation of this approach: C++ // CPP code to print alternate nodes // of a linked list using recursion #include <bits/stdc++.h> using namespace std; // A linked list node struct Node { int data; struct Node* next; }; // Inserting node at the beginning void push(struct Node** head_ref, int new_data) { struct Node* new_node = new Node(); new_node->data = new_data; new_node->next = (*head_ref); (*head_ref) = new_node; } // Function to find product of alternate // nodes of linked list. // The boolean flag isOdd is used to find // if the current node is even or odd. void productAlternateNodes(struct Node* node, int& prod, bool isOdd = true) { if (node == NULL) return; if (isOdd == true) prod = prod * (node->data); productAlternateNodes(node->next, prod, !isOdd); } // Driver code int main() { // Start with the empty list struct Node* head = NULL; // construct below list // 8 -> 23 -> 11 -> 29 -> 12 push(&head, 12); push(&head, 29); push(&head, 11); push(&head, 23); push(&head, 8); int prod = 1; productAlternateNodes(head, prod); cout << prod; return 0; } Java // Java code to print alternate nodes // of a linked list using recursion class GFG { // A linked list node static class Node { int data; Node next; }; // Inserting node at the beginning static Node push(Node head_ref, int new_data) { Node new_node = new Node(); new_node.data = new_data; new_node.next = (head_ref); (head_ref) = new_node; return head_ref; } static int prod; // Function to find product of alternate // nodes of linked list. // The boolean flag isOdd is used to find // if the current node is even or odd. static void productAlternateNodes(Node node, boolean isOdd) { if (node == null) return; if (isOdd == true) prod = prod * (node.data); productAlternateNodes(node.next, !isOdd); } // Driver code public static void main(String args[]) { // Start with the empty list Node head = null; // construct below list // 8 . 23 . 11 . 29 . 12 head = push(head, 12); head = push(head, 29); head = push(head, 11); head = push(head, 23); head = push(head, 8); prod = 1; productAlternateNodes(head, true); System.out.println( prod); } } // This code is contributed by Arnab Kundu Python3 # Python3 code to print alternate nodes # of a linked list using recursion # Link list node class Node: def __init__(self, data): self.data = data self.next = next # function to insert a node at the # beginning of the linked list def push(head_ref, new_data): # allocate node new_node = Node(0) # put in the data new_node.data = new_data # link the old list to the new node new_node.next = (head_ref) # move the head to point to the new node (head_ref) = new_node return head_ref prod = 1 # Function to find product of alternate # nodes of linked list. # The boolean flag isOdd is used to find # if the current node is even or odd. def productAlternateNodes(node, isOdd): global prod if (node == None): return if (isOdd == True): prod = prod * (node.data) productAlternateNodes(node.next, not isOdd) # Driver code # Start with the empty list head = None # construct below list # 8 -> 23 -> 11 -> 29 -> 12 head = push(head, 12) head = push(head, 29) head = push(head, 11) head = push(head, 23) head = push(head, 8) prod = 1 productAlternateNodes(head, True) print (prod) # This code is contributed by Arnab Kundu C# // C# code to print alternate nodes // of a linked list using recursion using System; class GFG { // A linked list node public class Node { public int data; public Node next; }; // Inserting node at the beginning static Node push(Node head_ref, int new_data) { Node new_node = new Node(); new_node.data = new_data; new_node.next = (head_ref); (head_ref) = new_node; return head_ref; } static int prod; // Function to find product of alternate // nodes of linked list. // The boolean flag isOdd is used to find // if the current node is even or odd. static void productAlternateNodes(Node node, bool isOdd) { if (node == null) return; if (isOdd == true) prod = prod * (node.data); productAlternateNodes(node.next, !isOdd); } // Driver code public static void Main(String []args) { // Start with the empty list Node head = null; // construct below list // 8 . 23 . 11 . 29 . 12 head = push(head, 12); head = push(head, 29); head = push(head, 11); head = push(head, 23); head = push(head, 8); prod = 1; productAlternateNodes(head, true); Console.WriteLine( prod); } } // This code is contributed by Rajput-Ji JavaScript <script> // Javascript code to print alternate nodes // of a linked list using recursion class Node { constructor() { this.data = 0; this.next = null; } } // Inserting node at the beginning function push(head_ref, new_data) { let new_node = new Node(); new_node.data = new_data; new_node.next = (head_ref); (head_ref) = new_node; return head_ref; } let prod; // Function to find product of alternate // nodes of linked list. // The boolean flag isOdd is used to find // if the current node is even or odd. function productAlternateNodes(node,isOdd) { if (node == null) return; if (isOdd == true) prod = prod * (node.data); productAlternateNodes(node.next, !isOdd); } // Driver code // Start with the empty list let head = null; // construct below list // 8 . 23 . 11 . 29 . 12 head = push(head, 12); head = push(head, 29); head = push(head, 11); head = push(head, 23); head = push(head, 8); prod = 1; productAlternateNodes(head, true); document.write( prod); // This code is contributed by avanitrachhadiya2155 </script> Output1056 Complexity Analysis: Time Complexity: O(N)Auxiliary Space: O(N) Comment More infoAdvertise with us Next Article Analysis of Algorithms V VishalBachchas Follow Improve Article Tags : DSA Technical Scripter 2018 Algorithms-Recursion Similar Reads Basics & PrerequisitesLogic Building ProblemsLogic building is about creating clear, step-by-step methods to solve problems using simple rules and principles. 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