Javascript Program To Find Decimal Equivalent Of Binary Linked List
Last Updated :
03 Sep, 2024
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Given a singly linked list of 0s and 1s find its decimal equivalent.
Input: 0->0->0->1->1->0->0->1->0
Output: 50
Input: 1->0->0
Output: 4
The decimal value of an empty linked list is considered as 0.
Initialize the result as 0. Traverse the linked list and for each node, multiply the result by 2 and add the node's data to it.
// Javascript Program to find decimal value
// of binary linked list
// Link list Node
class Node {
constructor() {
this.data = true;
this.next = null;
}
}
// Returns decimal value of binary
// linked list
function decimalValue(head) {
// Initialized result
let res = 0;
// Traverse linked list
while (head != null) {
// Multiply result by 2 and add
// head's data
res = (res << 1) +
(head.data ? 1 : 0);
// Move next
head = head.next;
}
return res;
}
// Utility function to create a
// new node.
function newNode(data) {
let temp = new Node();
temp.data = (data == 1 ?
true : false);
temp.next = null;
return temp;
}
// Driver code
// Start with the empty list
let head = newNode(1);
head.next = newNode(0);
head.next.next = newNode(1);
head.next.next.next = newNode(1);
console.log("Decimal value is " + decimalValue(head));
// This code is contributed by aashish1995
Output
Decimal value is 11
Complexity Analysis:
- Time Complexity: O(n) where n is the number of nodes in the given linked list.
- Auxiliary Space: O(1), no extra space is required, so it is a constant.
Another Approach(by reversing the Linked List):
Follow the below steps to solve the given problem
- First reverse the given linked list.
- Initialize a ans variable to store ans and pos variable to keep track of position of node in linked list.
- Perform the operation ans = ans + (rhead.data*(2**pos))%MOD)
- perform ans = ans%MOD
Below is the implementation of above approach:
// JavaScript program to find the decimal value
// of binary linked list
// node class
class Node{
constructor(data){
this.data = data;
this.left = null;
this.right = null;
}
}
function reverse(head){
if(head == null || head.next == null) return head;
let curr = head;
let prev = null;
let nxt = head.next;
while(nxt != null){
curr.next = prev;
prev = curr;
curr = nxt;
nxt = nxt.next;
}
curr.next = prev;
return curr;
}
function decimalValue(head){
let MOD = 1000000007;
let rhead = reverse(head);
let ans = 0;
let pos = 0;
while(rhead != null){
ans = (ans % MOD+(rhead.data*(2**pos)) % MOD) % MOD;
rhead = rhead.next;
pos += 1;
}
return ans;
}
// driver program to test above function
let head = new Node(1);
head.next = new Node(0);
head.next.next = new Node(1);
head.next.next.next= new Node(1);
console.log("Decimal Value is : " + decimalValue(head));
Output
Decimal Value is : 11
Complexity Analysis:
- Time Complexity: O(N) where N is the number of nodes in linked list.
- Auxiliary Space: O(1)
Please refer complete article on Decimal Equivalent of Binary Linked List for more details!
