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Add Two Numbers

Certification: Intermediate Level Accuracy: 40% Submissions: 5 Points: 10

Write a C program to add two numbers represented by linked lists. The digits are stored in reverse order, and each node in the linked list contains a single digit. You need to add the two numbers and return the sum as a linked list. Assume the two numbers do not contain any leading zero, except the number 0 itself.

Example 1
    
  
  • Input: l1 = [2,4,3], l2 = [5,6,4]
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  • Output: [7,0,8]
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  • Explanation: The numbers represented by the linked lists are 342 and 465 (in reverse order).
    342 + 465 = 807
    The result 807 is represented as [7,0,8] in reverse order.
    •
Example 2
    
  
  • Input: l1 = [0], l2 = [0]
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  • Output: [0]
    • 
  
  • Explanation: Both linked lists represent the number 0.
    0 + 0 = 0
    The result 0 is represented as [0] in the output linked list.
    •
Constraints
    
  
  • The number of nodes in each linked list is in the range [1, 100]
    • 
  
  • 0 ≤ Node.val ≤ 9
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  • It is guaranteed that the list represents a number that does not have leading zeros
    • 
  
  • The two linked lists may have different lengths
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  • You must solve the problem without modifying the input linked lists
    • 
  
  • Time Complexity: O(max(m,n)), where m and n are the lengths of the two lists
    • 
  
  • Space Complexity: O(max(m,n)), where m and n are the lengths of the two lists
    •
Linked ListTCS (Tata Consultancy Services)EY
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Hint
Solution

Solution Hints

    
  
  • Traverse both linked lists simultaneously and add the digits at the corresponding positions
    • 
  
  • Keep track of the carry value when the sum of two digits exceeds 9
    • 
  
  • Create a new linked list to store the result
    • 
  
  • Continue the traversal until both linked lists are completely traversed
    • 
  
  • Remember to handle the carry value after traversing both lists
    •

Steps to solve by this approach:

 Step 1: Create a dummy head node to simplify handling the result list.

 Step 2: Initialize a carry variable to 0 to keep track of any carry from adding digits.

 Step 3: Iterate through both lists simultaneously until both lists are exhausted and there's no carry left.

 Step 4: For each iteration, extract the digit from each list (or use 0 if the list is exhausted).

 Step 5: Add the digits along with the carry from the previous addition.

 Step 6: Create a new node with the value as the sum modulo 10 and update the carry as the sum divided by 10.

 Step 7: Move to the next nodes in both input lists and continue the process.

Submitted Code :