Search a in Singly Linked List

Search a specific node in Singly Linked List

Last Updated: 06 October, 2024 🕓 5 Mins

In this Linked List tutorial, we will see all about the search operation in singly linked list. In the search operation, we iterate the list and compare each node's data with the key if found that means key is present else not.

To search a node from a linked list, there are two approaches:

Iterative Approach

Recursive Approach

Search a key in a linked list using Iterative approach

  
  // Java program to search a key in a linked list using Iterative approach
  public class Node {
    int data;
    Node next;
  
    // Constructor
    Node(int data) {
      this.data = data;
      this.next = null;
    }
  }
  
  public class SearchUsingIterativeApproachInSLL {
    
    // Method to checks whether key is present in the linked list
    static void searchKey(Node head, int key) {
  
      // Initialize tempNode with the head of linked list
      Node tempNode = head;
  
      // Iterate over all the nodes
      while (tempNode != null) {
  
        // Key is present, if tempNode's data is equal to the key.
        if (tempNode.data == key) {
          System.out.println(key + " is PRESENT in the list.");
          return; // returning because key is found.
        }
  
        // Move to the next node
        tempNode = tempNode.next;
      }
  
      // Key is not present, if there is no node with data as key
      System.out.println(key + " is NOT PRESENT in the list.");
    }
  
    public static void main(String[] args) {
  
      // Create a linked list
      Node head = new Node(50);
      head.next = new Node(30);
      head.next.next = new Node(10);
      head.next.next.next = new Node(70);
      head.next.next.next.next = new Node(40);
  
      // Linked list will be created like this
      // 50 -> 30 -> 10 -> 70 -> 40
  
      // 10 is the Key to search in the linked list
      searchKey(head, 10);
  
      // 100 is the Key to search in the linked list
      searchKey(head, 100);
    }
  }

Search a key in a linked list using Recursive approach

  
  // Java program to search a key in a linked list using Recursive approach
  public class Node {
    int data;
    Node next;
  
    // Constructor
    Node(int data) {
      this.data = data;
      this.next = null;
    }
  }
  
  public class SearchUsingRecursiveApproachInSLL {
    // Checks whether the key is present in linked list
    static boolean searchKey(Node head, int key) {
  
      // If head is equal to null that means list is empty
      if (head == null)
        return false;
  
      // If key is present in the current node
      if (head.data == key)
        return true;
  
      // Recur for remaining list
      return searchKey(head.next, key);
    }
  
    public static void main(String[] args) {
  
      // Create a linked list
      Node head = new Node(50);
      head.next = new Node(30);
      head.next.next = new Node(10);
      head.next.next.next = new Node(70);
      head.next.next.next.next = new Node(40);
  
      // Linked list will be created like this
      // 50 -> 30 -> 10 -> 70 -> 40
  
      // Scenario: Key is present
      if (searchKey(head, 70))
        System.out.println("Key 70 is PRESENT in the list.");
      else
        System.out.println("Key 70 is NOT PRESENT in the list.");
  
      // Scenario: Key is not present
      if (searchKey(head, 5))
        System.out.println("Key 5 is PRESENT in the list.");
      else
        System.out.println("Key 5 is NOT PRESENT in the list.");
    }
  }