Find the largest node in Doubly linked list

Last Updated : 18 Jan, 2023

Given a doubly-linked list, find the largest node in the doubly linked list.

Examples:

Input: 10->8->4->23->67->88         Largest node is: 88 Output: 88  Input : 34->2->78->18->120->39->7         Largest node  is: 120 Output :120

Approach Used:

Initialize the temp and max pointer to head nodes.
Traverse the whole list.
if temp's data is greater than max's data, then put max = temp.
move on to the next node.

Implementation:

C++

/* C++ Program to find the largest  nodes in doubly linked list */ #include <iostream> using namespace std;  // Create a node of the doubly linked list  struct Node {      int data;      struct Node* next;      struct Node* prev;  };   /* UTILITY FUNCTIONS */ /* Function to insert a node at the  beginning of the Doubly Linked List */ void push(struct Node** head_ref, int new_data)  {      /* allocate node */     struct Node* new_node =      (struct Node*)malloc(sizeof(struct Node));       /* put in the data */     new_node->data = new_data;       /* since we are adding at the      beginning, prev is always NULL */     new_node->prev = NULL;       /* link the old list of the new node */     new_node->next = (*head_ref);       /* change prev of head node to new node */     if ((*head_ref) != NULL)          (*head_ref)->prev = new_node;       /* move the head to point to the new node */     (*head_ref) = new_node;  }   /* Function to find the largest  nodes in Doubly Linked List */ int LargestInDLL(struct Node** head_ref)  {      struct Node *max, *temp;       /* initialize two pointer temp      and max on the head node */     temp = max = *head_ref;       // traverse the whole doubly linked list      while (temp != NULL)      {           /* if temp's data is greater than          max's data, then put max = temp          and return max->data */         if (temp->data > max->data)              max = temp;           temp = temp->next;      }      return max->data;  }   // Driver code int main()  {      // Start with the empty list      struct Node* head = NULL;       // Let us create a linked list      push(&head, 20);      push(&head, 14);      push(&head, 181);      push(&head, 100);       cout << LargestInDLL(&head);      return 0;  }   // This code is contributed by shubhamsingh10

/* Program to find the largest    nodes in doubly linked list */ #include <stdio.h> #include <stdlib.h>  // Create a node of the doubly linked list struct Node {     int data;     struct Node* next;     struct Node* prev; };  /* UTILITY FUNCTIONS */ /* Function to insert a node at the beginning of the Doubly Linked List */ void push(struct Node** head_ref, int new_data) {     /* allocate node */     struct Node* new_node = (struct Node*)malloc(sizeof(struct Node));      /* put in the data */     new_node->data = new_data;      /* since we are adding at the      beginning, prev is always NULL */     new_node->prev = NULL;      /* link the old list of the new node */     new_node->next = (*head_ref);      /* change prev of head node to new node */     if ((*head_ref) != NULL)         (*head_ref)->prev = new_node;      /* move the head to point to the new node */     (*head_ref) = new_node; }  /* Function to find the largest     nodes in Doubly Linked List */ int LargestInDLL(struct Node** head_ref) {     struct Node *max, *temp;      /* initialize two pointer temp         and max on the head node */     temp = max = *head_ref;      // traverse the whole doubly linked list     while (temp != NULL) {          /* if temp's data is greater than            max's data, then put max = temp            and return max->data */         if (temp->data > max->data)             max = temp;          temp = temp->next;     }     return max->data; }  int main() {     // Start with the empty list     struct Node* head = NULL;      // Let us create a linked list     push(&head, 20);     push(&head, 14);     push(&head, 181);     push(&head, 100);      printf("%d", LargestInDLL(&head));     return 0; }

Java

// Java Program to find the largest // nodes in doubly linked list class GFG {      // Create node of the doubly linked list     static class Node {         int data;         Node next;         Node prev;     };      // UTILITY FUNCTIONS     // Function to insert a node at the     // beginning of the Doubly Linked List     static Node push(Node head_ref, int new_data)     {         // allocate node         Node new_node = new Node();          // put in the data         new_node.data = new_data;          // since we are adding at the         // beginning, prev is always null         new_node.prev = null;          // link the old list of the new node         new_node.next = (head_ref);          // change prev of head node to new node         if ((head_ref) != null)             (head_ref).prev = new_node;          // move the head to point to the new node         (head_ref) = new_node;         return head_ref;     }      // Function to find the largest     // nodes in Doubly Linked List     static int LargestInDLL(Node head_ref)     {         Node max, temp;          // initialize two pointer temp         // and max on the head node         temp = max = head_ref;          // traverse the whole doubly linked list         while (temp != null) {              // if temp's data is greater than             // max's data, then put max = temp             // and return max.data             if (temp.data > max.data)                 max = temp;              temp = temp.next;         }         return max.data;     }      public static void main(String args[])     {         // Start with the empty list         Node head = null;          // Let us create a linked list         head = push(head, 20);         head = push(head, 14);         head = push(head, 181);         head = push(head, 100);          System.out.printf("%d", LargestInDLL(head));     } }  // This code is contributed by Arnab Kundu

Python3

# Python3 program to find largest  # node in doubly linked list  # Node of the doubly linked list  class Node:           def __init__(self, data):          self.data = data          self.prev = None         self.next = None  # Function to find pair whose product # equal to given value x def pairProduct(head, x):      # Set two pointers,     # first to the beginning of DLL     # and second to the end of DLL.     first = head     second = head     while (second.next != None):         second = second.next      # To track if we find a pair or not     found = False      # The loop terminates when either of two pointers     # become None, or they cross each other (second.next     # == first), or they become same (first == second)     while (first != None and            second != None and first != second and             second.next != first) :                         # pair found         if ((first.data * second.data) == x) :             found = True             print("(" , first.data,                    ", ", second.data, ")")              # move first in forward direction             first = first.next              # move second in backward direction             second = second.prev                  else :             if ((first.data * second.data) < x):                 first = first.next             else:                 second = second.prev          # if pair is not present     if (found == False):         print( "No pair found")  # A utility function to insert a new node at the # beginning of doubly linked list def push( head, data):      temp = Node(0)     temp.data = data     temp.next = temp.prev = None     if (head == None):         (head) = temp     else :         temp.next = head         (head).prev = temp         (head) = temp     return head      """ Function to find the largest  nodes in Doubly Linked List """ def LargestInDLL( head_ref):      max = None     temp = None      """ initialize two pointer temp      and max on the head node """     temp = max = head_ref      # traverse the whole doubly linked list     while (temp != None):           """ if temp's data is greater than         max's data, then put max = temp         and return max.data """         if (temp.data > max.data):             max = temp          temp = temp.next          return max.data  # Driver Code if __name__ == "__main__":       # Start with the empty list     head = None      # Let us create a linked list     head = push(head, 20)     head = push(head, 14)     head = push(head, 181)     head = push(head, 100)      print( LargestInDLL(head))      # This code is contributed by Arnab Kundu

// C# Program to find the largest // nodes in doubly linked list using System;  class GFG {      // Create node of the doubly linked list     public class Node {         public int data;         public Node next;         public Node prev;     };      // UTILITY FUNCTIONS     // Function to insert a node at the     // beginning of the Doubly Linked List     static Node push(Node head_ref, int new_data)     {         // allocate node         Node new_node = new Node();          // put in the data         new_node.data = new_data;          // since we are adding at the         // beginning, prev is always null         new_node.prev = null;          // link the old list of the new node         new_node.next = (head_ref);          // change prev of head node to new node         if ((head_ref) != null)             (head_ref).prev = new_node;          // move the head to point to the new node         (head_ref) = new_node;         return head_ref;     }      // Function to find the largest     // nodes in Doubly Linked List     static int LargestInDLL(Node head_ref)     {         Node max, temp;          // initialize two pointer temp         // and max on the head node         temp = max = head_ref;          // traverse the whole doubly linked list         while (temp != null) {              // if temp's data is greater than             // max's data, then put max = temp             // and return max.data             if (temp.data > max.data)                 max = temp;              temp = temp.next;         }         return max.data;     }      // Driver code     public static void Main(String[] args)     {         // Start with the empty list         Node head = null;          // Let us create a linked list         head = push(head, 20);         head = push(head, 14);         head = push(head, 181);         head = push(head, 100);          Console.Write("{0}", LargestInDLL(head));     } }  // This code contributed by Rajput-Ji

JavaScript

<script>     // javascript Program to find the largest     // nodes in doubly linked list         // Create node of the doubly linked list     class Node {         constructor(val) {             this.data = val;             this.prev = null;             this.next = null;         }     }      // UTILITY FUNCTIONS     // Function to insert a node at the     // beginning of the Doubly Linked List     function push(head_ref , new_data) {         // allocate node         var new_node = new Node();          // put in the data         new_node.data = new_data;          // since we are adding at the         // beginning, prev is always null         new_node.prev = null;          // link the old list of the new node         new_node.next = (head_ref);          // change prev of head node to new node         if ((head_ref) != null)             (head_ref).prev = new_node;          // move the head to point to the new node         (head_ref) = new_node;         return head_ref;     }      // Function to find the largest     // nodes in Doubly Linked List     function LargestInDLL(head_ref) {         var max, temp;          // initialize two pointer temp         // and max on the head node         temp = max = head_ref;          // traverse the whole doubly linked list         while (temp != null) {              // if temp's data is greater than             // max's data, then put max = temp             // and return max.data             if (temp.data > max.data)                 max = temp;              temp = temp.next;         }         return max.data;     }           // Start with the empty list     var head = null;      // Let us create a linked list     head = push(head, 20);     head = push(head, 14);     head = push(head, 181);     head = push(head, 100);      document.write(LargestInDLL(head));  // This code contributed by umadevi9616  </script>