Decimal Equivalent of Binary Linked List
Last Updated : 28 Dec, 2023
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.
C++ // C++ Program to find decimal value of // binary linked list #include <bits/stdc++.h> using namespace std; /* Link list Node */ class Node { public: bool data; Node* next; }; /* Returns decimal value of binary linked list */ int decimalValue(Node *head) { // Initialized result int res = 0; // Traverse linked list while (head != NULL) { // Multiply result by 2 and add // head's data res = (res << 1) + head->data; // Move next head = head->next; } return res; } // Utility function to create a new node. Node *newNode(bool data) { Node *temp = new Node; temp->data = data; temp->next = NULL; return temp; } /* Driver program to test above function*/ int main() { /* Start with the empty list */ Node* head = newNode(1); head->next = newNode(0); head->next->next = newNode(1); head->next->next->next = newNode(1); cout << "Decimal value is " << decimalValue(head); return 0; } // This is code is contributed by rathbhupendra // C Program to find decimal value of // binary linked list #include<iostream> using namespace std; /* Link list Node */ struct Node { bool data; struct Node* next; }; /* Returns decimal value of binary linked list */ int decimalValue(struct Node *head) { // Initialized result int res = 0; // Traverse linked list while (head != NULL) { // Multiply result by 2 and add // head's data res = (res << 1) + head->data; // Move next head = head->next; } return res; } // Utility function to create a new node. Node *newNode(bool data) { struct Node *temp = new Node; temp->data = data; temp->next = NULL; return temp; } /* Driver program to test above function*/ int main() { /* Start with the empty list */ struct Node* head = newNode(1); head->next = newNode(0); head->next->next = newNode(1); head->next->next->next = newNode(1); cout << "Decimal value is " << decimalValue(head); return 0; } // Java Program to find decimal value of // binary linked list class GFG { // Link list Node / static class Node { boolean data; Node next; }; // Returns decimal value of binary linked list / static int decimalValue( Node head) { // Initialized result int 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. static Node newNode(int data) { Node temp = new Node(); temp.data = (data==1? true:false); temp.next = null; return temp; } // Driver code/ public static void main(String args[]) { // Start with the empty list / Node head = newNode(1); head.next = newNode(0); head.next.next = newNode(1); head.next.next.next = newNode(1); System.out.print( "Decimal value is "+decimalValue(head)); } } // This code is contributed by Arnab Kundu # Python3 program to find decimal value # of binary linked list # Node Class class Node: # Function to initialise the # node object def __init__(self, data): # Assign data self.data = data # Initialize next as null self.next = None # Linked List class contains # a Node object class LinkedList: # Function to initialize head def __init__(self): self.head = None # Returns decimal value of binary # linked list def decimalValue(self, head): # Initialized result res = 0 # Traverse linked list while head: # Multiply result by 2 and # add head's data res = (res << 1) + head.data # Move Next head = head.next return res # Driver code if __name__ == '__main__': #Start with the empty list llist = LinkedList() llist.head = Node(1) llist.head.next = Node(0) llist.head.next.next = Node(1) llist.head.next.next.next = Node(1) print("Decimal Value is {}".format( llist.decimalValue(llist.head))) # This code is contributed by Mohit Jangra // C# Program to find decimal value of // binary linked list using System; class GFG { // Link list Node / public class Node { public Boolean data; public Node next; }; // Returns decimal value of binary linked list static int decimalValue( Node head) { // Initialized result int 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. static Node newNode(int data) { Node temp = new Node(); temp.data = (data == 1 ? true : false); temp.next = null; return temp; } // Driver code public static void Main(String []args) { // Start with the empty list Node head = newNode(1); head.next = newNode(0); head.next.next = newNode(1); head.next.next.next = newNode(1); Console.WriteLine("Decimal value is " + decimalValue(head)); } } // This code is contributed by Rajput-Ji <script> // 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 var 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) { var temp = new Node(); temp.data = (data == 1 ? true : false); temp.next = null; return temp; } // Driver code/ // Start with the empty list / var head = newNode(1); head.next = newNode(0); head.next.next = newNode(1); head.next.next.next = newNode(1); document.write("Decimal value is " + decimalValue(head)); // This code contributed by aashish1995 </script> OutputDecimal value is 11
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
1) First reverse the given linked list.
2) Initialize a ans variable to store ans and pos variable to keep track of position of node in linked list.
3) Perform the operation ans = ans + (rhead.data*(2**pos))%MOD)
4) perform ans = ans%MOD
Below is the implementation of above approach:
C++ #include<bits/stdc++.h> using namespace std; // C++ Program to find decimal value // of binary linked list // node structure struct Node{ int data; Node* next; Node(int data){ this->data = data; this->next = NULL; } }; long long unsigned int power(int num,int count){ if(count ==0) return 1; if(count%2==0) return (power(num,count/2)%1000000007)*(power(num,count/2)%1000000007); else return num*(power(num,count/2)%1000000007)*(power(num,count/2)%1000000007);; } Node* reverse(Node* head){ if(head == NULL || head->next == NULL) return head; Node* curr = head; Node* prev = NULL; Node* nxt = head->next; while(nxt != NULL){ curr->next = prev; prev = curr; curr = nxt; nxt = nxt->next; } curr->next = prev; return curr; } int decimalValue(Node* head){ int MOD = 1000000007; Node* rhead = reverse(head); int ans = 0; int pos = 0; while(rhead != NULL){ ans = (ans%MOD + ((rhead->data)*power(2,pos)) % MOD) % MOD; rhead = rhead->next; pos++; } return ans; } int main(){ Node* head = new Node(1); head->next = new Node(0); head->next->next = new Node(1); head->next->next->next = new Node(1); cout<<"Decimal Value is : "<<decimalValue(head); } // Java implementation to find non-leaf // count of a given Binary tree import java.util.*; // class to represent the tree node class Node{ public int data; public Node next; public Node(int item){ data = item; next = null; } } public class LinkedList{ static int power(int num, int count){ if(count ==0) return 1; if(count % 2 ==0) return (power(num,count/2)%1000000007)*(power(num,count/2)%1000000007); else return num*(power(num,count/2)%1000000007)*(power(num,count/2)%1000000007); } static Node reverse(Node head){ if(head == null || head.next == null) return head; Node curr = head; Node prev = null; Node nxt = head.next; while(nxt != null){ curr.next = prev; prev = curr; curr = nxt; nxt = nxt.next; } curr.next = prev; return curr; } static int decimalValue(Node head){ Node rhead = reverse(head); int ans = 0; int pos = 0; while(rhead != null){ ans = (ans % 1000000007 + ((rhead.data)*((int)power(2,pos))) % 1000000007) % 1000000007; rhead = rhead.next; pos++; } return ans; } // driver code to test above function public static void main(String args[]){ Node head = new Node(1); head.next = new Node(0); head.next.next = new Node(1); head.next.next.next = new Node(1); // function call System.out.println("Decimal Value is : " + decimalValue(head)); } } # Python3 program to find decimal value # of binary linked list # Node Class class Node: # Function to initialise the # node object def __init__(self, data): # Assign data self.data = data # Initialize next as null self.next = None def reverse(head): if(head == None or head.next == None): return head curr = head prev = None nxt = head.next while(nxt): curr.next = prev prev = curr curr = nxt nxt = nxt.next curr.next = prev return curr def decimalValue(head): MOD=10**9+7 rhead = reverse(head) ans = 0 pos = 0 while rhead: ans = (ans % MOD+(rhead.data*(2**pos)) % MOD) % MOD rhead = rhead.next pos += 1 return ans head = Node(1) head.next = Node(0) head.next.next = Node(1) head.next.next.next = Node(1) print("Decimal Value is :", end =" ") print(decimalValue(head)) # THIS CODE IS CONTRIBUTED BY YASH AGARWAL(YASHAGARWAL2852002) using System; // C# Program to find decimal value // of binary linked list class GFG{ public class Node{ public int data; public Node next; public Node(int data){ this.data = data; this.next = null; } } static int power(int num, int count){ if(count == 0) return 1; if(count%2==0) return (power(num,count/2)%1000000007)*(power(num,count/2)%1000000007); else return num*(power(num,count/2)%1000000007)*(power(num,count/2)%1000000007); } static Node reverse(Node head){ if(head == null || head.next == null) return head; Node curr = head; Node prev = null; Node nxt = head.next; while(nxt != null){ curr.next = prev; prev = curr; curr = nxt; nxt = nxt.next; } curr.next = prev; return curr; } static int decimalValue(Node head){ int MOD = 1000000007; Node rhead = reverse(head); int ans = 0; int pos = 0; while(rhead != null){ ans = (ans%MOD + ((rhead.data)*power(2,pos)) % MOD) % MOD; rhead = rhead.next; pos++; } return ans; } public static void Main(){ Node head = new Node(1); head.next = new Node(0); head.next.next = new Node(1); head.next.next.next = new Node(1); Console.WriteLine("Decimal Value is : " + decimalValue(head)); } } // 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)); OutputDecimal Value is : 11
Time Complexity: O(N) where N is the number of nodes in linked list.
Auxiliary Space: O(1)