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Find minimum and maximum elements in singly Circular Linked List

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Given a singly circular linked list of N           nodes. The task is to find the smallest and largest elements in the circular linked list.

Examples:  

Input : List = 99->11->22->33->44->55->66
Output : Minimum = 11, Maximum = 99

Input : List = 12->11->9->33->125->6->99
Output : Minimum = 6, Maximum = 125 

The idea is to traverse the circular linked list while the last node is not reached and initialize the max and min variables to INT_MIN and INT_MAX respectively. After that, check the condition that if the max value is less than the head value, then the head value is assigned to the max or if the min value is greater than the head value, then the head value is assigned to the min, otherwise the head point to the next node. Continue this process until the last node.

Algorithm:

Step 1: Create a function named “printMinMax” that takes the head node of a circular linked list as an input parameter.
Step 2: Create two integer variables min and max and initialize them to Integer.MAX_VALUE and Integer.MIN_VALUE, respectively. 
Step 3: Define a pointer “current” and initialize it with the head node.
Step 4: Start a while loop till current.next is not equal to null.
             a. In each iteration of the while loop, compare the data of the current node with the values of min and max. If the data is lesser than the                       value of min, assign the data to the min variable. If the data is greater than the value of max, assign the data to the max variable.
             b. Update the current pointer to the next node. 
Step 5: Now after the while loop,  print the values of min and max statement.
Step 6: Create a function named “insertNode” which takes a head node of a circular linked list and a data value to be inserted into the linked list an              input parameter.
Step 7: Create a new node with the given data value and check whether the node is created successfully or not.
Step 8: Assign the new node’s next pointer to the node itself if the linked list is empty, and then return the new node as the head node. 
Step 9: If the linked list is not empty, traverse the linked list until the last node using a while loop.
Step 10: Give the head node the new node’s next pointer and then give it back.        
Step 11: Create a function named “displayList” which take the head node of a circular linked list and prints the values of all the nodes in the linked                  list as an input parameter.
Step 12: Use a do-while loop to iteratively navigate the linked list until you reach the head node once more after initializing a pointer with the head                node.
Step 13: Print the value of the current node using the System on each iteration of the do-while loop. out. move the current pointer to the following                node and use the print statement

Below is the implementation of the above approach: 

C++

// C++ program to find minimum and maximum
// value from singly circular linked list
#include <bits/stdc++.h>
using namespace std;
 
// structure for a node
struct Node {
    int data;
    struct Node* next;
};
 
// Function to print minimum and maximum
// nodes of the circular linked list
void printMinMax(struct Node** head)
{
    // check list is empty
    if (*head == NULL) {
        return;
    }
 
    // pointer for traversing
    struct Node* current;
 
    // initialize head to current pointer
    current = *head;
 
    // initialize max int value to min
    // initialize min int value to max
    int min = INT_MAX, max = INT_MIN;
 
    // While last node is not reached
    do {
 
        // If current node data is lesser for min
        // then replace it
        if (current->data < min) {
            min = current->data;
        }
 
        // If current node data is greater for max
        // then replace it
        if (current->data > max) {
            max = current->data;
        }
 
        current = current->next;
    }
     while(current != *head);
 
    cout << "\nMinimum = " << min << ", Maximum = " << max;
}
 
// Function to insert a node at the end of
// a Circular linked list
void insertNode(struct Node** head, int data)
{
    struct Node* current = *head;
    // Create a new node
    struct Node* newNode = new Node;
 
    // check node is created or not
    if (!newNode) {
        printf("\nMemory Error\n");
        return;
    }
 
    // insert data into newly created node
    newNode->data = data;
 
    // check list is empty
    // if not have any node then
    // make first node it
    if (*head == NULL) {
        newNode->next = newNode;
        *head = newNode;
        return;
    }
 
    // if list have already some node
    else {
 
        // move first node to last node
        while (current->next != *head) {
            current = current->next;
        }
 
        // put first or head node address
        // in new node link
        newNode->next = *head;
 
        // put new node address into
        // last node link(next)
        current->next = newNode;
    }
}
 
// Function to print the Circular linked list
void displayList(struct Node* head)
{
 
    struct Node* current = head;
 
    // if list is empty simply show message
    if (head == NULL) {
        printf("\nDisplay List is empty\n");
        return;
    }
 
    // traverse first to last node
    else {
        do {
            printf("%d ", current->data);
            current = current->next;
        } while (current != head);
    }
}
 
// Driver Code
int main()
{
    struct Node* Head = NULL;
 
    insertNode(&Head, 99);
    insertNode(&Head, 11);
    insertNode(&Head, 22);
    insertNode(&Head, 33);
    insertNode(&Head, 44);
    insertNode(&Head, 55);
    insertNode(&Head, 66);
 
    cout << "Initial List: ";
 
    displayList(Head);
 
    printMinMax(&Head);
 
    return 0;
}

                    

Java

// Java program to find minimum and maximum
// value from singly circular linked list
class GFG
{
 
// structure for a node
static class Node
{
    int data;
    Node next;
};
 
// Function to print minimum and maximum
// nodes of the circular linked list
static void printMinMax(Node head)
{
    // check list is empty
    if (head == null)
    {
        return;
    }
 
    // pointer for traversing
    Node current;
 
    // initialize head to current pointer
    current = head;
 
    // initialize max int value to min
    // initialize min int value to max
    int min = Integer.MAX_VALUE, max = Integer.MIN_VALUE;
 
    // While last node is not reached
    while (current.next != head)
    {
 
        // If current node data is lesser for min
        // then replace it
        if (current.data < min)
        {
            min = current.data;
        }
 
        // If current node data is greater for max
        // then replace it
        if (current.data > max)
        {
            max = current.data;
        }
 
        current = current.next;
    }
 
    System.out.println( "\nMinimum = " + min + ", Maximum = " + max);
}
 
// Function to insert a node at the end of
// a Circular linked list
static Node insertNode(Node head, int data)
{
    Node current = head;
     
    // Create a new node
    Node newNode = new Node();
 
    // check node is created or not
    if (newNode == null)
    {
        System.out.printf("\nMemory Error\n");
        return null;
    }
 
    // insert data into newly created node
    newNode.data = data;
 
    // check list is empty
    // if not have any node then
    // make first node it
    if (head == null)
    {
        newNode.next = newNode;
        head = newNode;
        return head;
    }
 
    // if list have already some node
    else
    {
 
        // move first node to last node
        while (current.next != head)
        {
            current = current.next;
        }
 
        // put first or head node address
        // in new node link
        newNode.next = head;
 
        // put new node address into
        // last node link(next)
        current.next = newNode;
    }
    return head;
}
 
// Function to print the Circular linked list
static void displayList(Node head)
{
 
    Node current = head;
 
    // if list is empty simply show message
    if (head == null)
    {
        System.out.printf("\nDisplay List is empty\n");
        return;
    }
 
    // traverse first to last node
    else
    {
        do
        {
            System.out.printf("%d ", current.data);
            current = current.next;
        } while (current != head);
    }
}
 
// Driver Code
public static void main(String args[])
{
    Node Head = null;
 
    Head=insertNode(Head, 99);
    Head=insertNode(Head, 11);
    Head=insertNode(Head, 22);
    Head=insertNode(Head, 33);
    Head=insertNode(Head, 44);
    Head=insertNode(Head, 55);
    Head=insertNode(Head, 66);
 
    System.out.println("Initial List: ");
 
    displayList(Head);
 
    printMinMax(Head);
}
}
 
// This code is contributed by Arnab Kundu

                    

Python3

# Python3 program to find minimum and maximum
# value from singly circular linked list
  
# structure for a node
class Node:
     
    def __init__(self):
         
        self.data = 0
        self.next = None
     
# Function to print minimum and maximum
# nodes of the circular linked list
def printMinMax(head):
 
    # check list is empty
    if (head == None):
        return;
  
    # initialize head to current pointer
    current = head;
  
    # initialize max int value to min
    # initialize min int value to max
    min = 1000000000
    max = -1000000000;
  
    # While last node is not reached
    while True:
  
        # If current node data is lesser for min
        # then replace it
        if (current.data < min):
            min = current.data;
  
        # If current node data is greater for max
        # then replace it
        if (current.data > max):
            max = current.data;
  
        current = current.next;       
        if(current == head):
            break   
    print('Minimum = {}, Maximum = {}'.format(min, max))
  
# Function to insert a node at the end of
# a Circular linked list
def insertNode(head, data):
    current = head;
     
    # Create a new node
    newNode = Node()
  
    # check node is created or not
    if not newNode:
        print("\nMemory Error");
        return head
  
    # insert data into newly created node
    newNode.data = data;
  
    # check list is empty
    # if not have any node then
    # make first node it
    if (head == None):
        newNode.next = newNode;
        head = newNode;
        return head
  
    # if list have already some node
    else:
  
        # move first node to last node
        while (current.next != head):
            current = current.next;
  
        # put first or head node address
        # in new node link
        newNode.next = head;
  
        # put new node address into
        # last node link(next)
        current.next = newNode;       
    return head
  
# Function to print the Circular linked list
def displayList(head):
    current = head;
  
    # if list is empty simply show message
    if (head == None):
        print("\nDisplay List is empty");
        return;
  
    # traverse first to last node
    else:
         
        while True:
            print(current.data, end=' ');
            current = current.next;          
            if(current==head):
                break
    print()
  
# Driver Code
if __name__=='__main__':
     
    Head = None;
  
    Head = insertNode(Head, 99);
    Head = insertNode(Head, 11);
    Head = insertNode(Head, 22);
    Head = insertNode(Head, 33);
    Head = insertNode(Head, 44);
    Head = insertNode(Head, 55);
    Head = insertNode(Head, 66);
  
    print("Initial List: ", end = '')
  
    displayList(Head);
  
    printMinMax(Head);
  
# This code is contributed by rutvik_56

                    

C#

// C# program to find minimum and maximum
// value from singly circular linked list
using System;
     
class GFG
{
 
// structure for a node
public class Node
{
    public int data;
    public Node next;
};
 
// Function to print minimum and maximum
// nodes of the circular linked list
static void printMinMax(Node head)
{
    // check list is empty
    if (head == null)
    {
        return;
    }
 
    // pointer for traversing
    Node current;
 
    // initialize head to current pointer
    current = head;
 
    // initialize max int value to min
    // initialize min int value to max
    int min = int.MaxValue, max = int.MinValue;
 
    // While last node is not reached
    while (current.next != head)
    {
 
        // If current node data is lesser for min
        // then replace it
        if (current.data < min)
        {
            min = current.data;
        }
 
        // If current node data is greater for max
        // then replace it
        if (current.data > max)
        {
            max = current.data;
        }
 
        current = current.next;
    }
 
    Console.WriteLine( "\nMinimum = " + min + ", Maximum = " + max);
}
 
// Function to insert a node at the end of
// a Circular linked list
static Node insertNode(Node head, int data)
{
    Node current = head;
     
    // Create a new node
    Node newNode = new Node();
 
    // check node is created or not
    if (newNode == null)
    {
        Console.Write("\nMemory Error\n");
        return null;
    }
 
    // insert data into newly created node
    newNode.data = data;
 
    // check list is empty
    // if not have any node then
    // make first node it
    if (head == null)
    {
        newNode.next = newNode;
        head = newNode;
        return head;
    }
 
    // if list have already some node
    else
    {
 
        // move first node to last node
        while (current.next != head)
        {
            current = current.next;
        }
 
        // put first or head node address
        // in new node link
        newNode.next = head;
 
        // put new node address into
        // last node link(next)
        current.next = newNode;
    }
    return head;
}
 
// Function to print the Circular linked list
static void displayList(Node head)
{
 
    Node current = head;
 
    // if list is empty simply show message
    if (head == null)
    {
        Console.Write("\nDisplay List is empty\n");
        return;
    }
 
    // traverse first to last node
    else
    {
        do
        {
            Console.Write("{0} ", current.data);
            current = current.next;
        } while (current != head);
    }
}
 
// Driver Code
public static void Main()
{
    Node Head = null;
 
    Head=insertNode(Head, 99);
    Head=insertNode(Head, 11);
    Head=insertNode(Head, 22);
    Head=insertNode(Head, 33);
    Head=insertNode(Head, 44);
    Head=insertNode(Head, 55);
    Head=insertNode(Head, 66);
 
    Console.WriteLine("Initial List: ");
 
    displayList(Head);
 
    printMinMax(Head);
}
}
 
/* This code contributed by PrinciRaj1992 */

                    

Javascript

<script>
// javascript program to find minimum and maximum
// value from singly circular linked list    
// structure for a node
class Node {
    constructor() {
        this.data = 0;
        this.next = null;
    }
}
 
// Function to print minimum and maximum
// nodes of the circular linked list
function printMinMax(head) {
    // check list is empty
    if (head == null) {
        return;
    }
 
    // pointer for traversing
    var current;
 
    // initialize head to current pointer
    current = head;
 
    // initialize max var value to min
    // initialize min var value to max
    var min = Number.MAX_VALUE, max = Number.MIN_VALUE;
 
    // While last node is not reached
    while (current.next != head) {
 
        // If current node data is lesser for min
        // then replace it
        if (current.data < min) {
            min = current.data;
        }
 
        // If current node data is greater for max
        // then replace it
        if (current.data > max) {
            max = current.data;
        }
 
        current = current.next;
    }
 
    document.write("<br/>Minimum = " + min + ", Maximum = " + max);
}
 
// Function to insert a node at the end of
// a Circular linked list
function insertNode(head , data) {
    var current = head;
 
    // Create a new node
    var newNode = new Node();
 
    // check node is created or not
    if (newNode == null) {
        document.write("<br/>Memory Error\n");
        return null;
    }
 
    // insert data into newly created node
    newNode.data = data;
 
    // check list is empty
    // if not have any node then
    // make first node it
    if (head == null) {
        newNode.next = newNode;
        head = newNode;
        return head;
    }
 
    // if list have already some node
    else {
 
        // move first node to last node
        while (current.next != head) {
            current = current.next;
        }
 
        // put first or head node address
        // in new node link
        newNode.next = head;
 
        // put new node address into
        // last node link(next)
        current.next = newNode;
    }
    return head;
}
 
// Function to print the Circular linked list
function displayList(head) {
 
    var current = head;
 
    // if list is empty simply show message
    if (head == null) {
        document.write("<br/>Display List is empty<br/>");
        return;
    }
 
    // traverse first to last node
    else {
        do {
            document.write(current.data+" ");
            current = current.next;
        } while (current != head);
    }
}
 
// Driver Code
     
var Head = null;
 
Head = insertNode(Head, 99);
Head = insertNode(Head, 11);
Head = insertNode(Head, 22);
Head = insertNode(Head, 33);
Head = insertNode(Head, 44);
Head = insertNode(Head, 55);
Head = insertNode(Head, 66);
   
document.write("Initial List: ");
 
displayList(Head);
 
printMinMax(Head);
 
// This code contributed by umadevi9616
</script>

                    

Output
Initial List: 99 11 22 33 44 55 66 
Minimum = 11, Maximum = 99

Complexity Analysis:

  • Time Complexity: O(n), as we are using a loop to traverse n times. Where n is the number of nodes in the linked list.
  • Auxiliary Space: O(1), as we are not using any extra space.


Last Updated : 21 Mar, 2023
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