Javascript Program For Searching An Element In A Linked List (original) (raw)

Last Updated : 09 Sep, 2024

Write a function that searches a given key 'x' in a given singly linked list. The function should return true if x is present in linked list and false otherwise.

bool search(Node *head, int x)

For example, if the key to be searched is 15 and linked list is 14->21->11->30->10, then function should return false. If key to be searched is 14, then the function should return true.

**Iterative Solution:

  1. Initialize a node pointer, current = head.
  2. Do following while current is not NULL
    a) current->key is equal to the key being searched return true.
    b) current = current->next
  3. Return false

Following is iterative implementation of above algorithm to search a given key.

JavaScript `

// Iterative javascript program // to search an element // in linked list

//Node class class Node { constructor(d) { this.data = d; this.next = null; } }

// Linked list class

// Head of list let head;

// Inserts a new node at the front of the list function push(new_data) { // Allocate new node and putting data let new_node = new Node(new_data);

// Make next of new node as head
new_node.next = head;

// Move the head to point to new Node
head = new_node;

}

// Checks whether the value // x is present in linked list function search(head, x) { // Initialize current let current = head;

while (current != null) {
    if (current.data == x)

        // Data found
        return true;
    current = current.next;
}

// Data not found
return false;

}

// Driver code

// Start with the empty list // Use push() to construct list // 14->21->11->30->10 push(10); push(30); push(11); push(21); push(14);

if (search(head, 21)) console.log("Yes"); else console.log("No"); // This code contributed by aashish1995

`

**Complexity Analysis:

**Recursive Solution:

**bool search(head, x)

  1. If head is NULL, return false.
  2. If head's key is same as x, return true;
  3. Else return search(head->next, x)

Following is the recursive implementation of the above algorithm to search a given key.

JavaScript `

// Recursive javascript program to search // an element in linked list

// Node class class Node { constructor(val) { this.data = val; this.next = null; } }

// Linked list class // Head of list let head;

// Inserts a new node at the front // of the list function push(new_data) { // Allocate new node and putting data let new_node = new Node(new_data);

// Make next of new node as head
new_node.next = head;

// Move the head to point to new Node
head = new_node;

}

// Checks whether the value x is present // in linked list function search(head, x) { // Base case if (head == null) return false;

// If key is present in current node,
// return true
if (head.data == x)
    return true;

// Recur for remaining list
return search(head.next, x);

}

// Driver code

// Start with the empty list // Use push() to construct list // 14->21->11->30->10 push(10); push(30); push(11); push(21); push(14);

if (search(head, 21)) console.log("Yes"); else console.log("No");

// This code contributed by gauravrajput1

`

Complexity Analysis:

Please refer complete article on Search an element in a Linked List (Iterative and Recursive) for more details!

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