In this guide, you will get 2816. Double a Number Represented as a Linked List LeetCode Solution with the best time and space complexity. The solution to Double a Number Represented as a Linked List problem is provided in various programming languages like C++, Java, and Python. This will be helpful for you if you are preparing for placements, hackathons, interviews, or practice purposes. The solutions provided here are very easy to follow and include detailed explanations.
Problem Statement of Double a Number Represented as a Linked List
You are given the head of a non-empty linked list representing a non-negative integer without leading zeroes.
Return the head of the linked list after doubling it.
Example 1:
Input: head = [1,8,9]
Output: [3,7,8]
Explanation: The figure above corresponds to the given linked list which represents the number 189. Hence, the returned linked list represents the number 189 * 2 = 378.
Example 2:
Input: head = [9,9,9]
Output: [1,9,9,8]
Explanation: The figure above corresponds to the given linked list which represents the number 999. Hence, the returned linked list reprersents the number 999 * 2 = 1998.
Constraints:
The number of nodes in the list is in the range [1, 104]
0 <= Node.val <= 9
The input is generated such that the list represents a number that does not have leading zeros, except the number 0 itself.
2816. Double a Number Represented as a Linked List LeetCode Solution in C++
class Solution {
public:
ListNode* doubleIt(ListNode* head) {
if (getCarry(head) == 1)
return new ListNode(1, head);
return head;
}
private:
int getCarry(ListNode* node) {
int val = node->val * 2;
if (node->next != nullptr)
val += getCarry(node->next);
node->val = val % 10;
return val / 10;
}
}; /* code provided by PROGIEZ */
2816. Double a Number Represented as a Linked List LeetCode Solution in Java
class Solution {
public ListNode doubleIt(ListNode head) {
if (getCarry(head) == 1)
return new ListNode(1, head);
return head;
}
private int getCarry(ListNode node) {
int val = node.val * 2;
if (node.next != null)
val += getCarry(node.next);
node.val = val % 10;
return val / 10;
}
} // code provided by PROGIEZ
2816. Double a Number Represented as a Linked List LeetCode Solution in Python
class Solution:
def doubleIt(self, head: ListNode | None) -> ListNode | None:
def getCarry(node: ListNode | None) -> ListNode | None:
val = node.val * 2
if node.next:
val += getCarry(node.next)
node.val = val % 10
return val // 10
if getCarry(head) == 1:
return ListNode(1, head)
return head # code by PROGIEZ
