700313. Subtraction in Linked List
Here is the detailed Markdown blog post for the "Subtraction in Linked List" problem:
Subtraction in Linked List
Summary
Given a singly linked list and an integer value, subtract that value from all nodes in the list. The task is to write a function that takes the head of the linked list and the integer value as input and returns the modified linked list.
This problem involves working with linked lists and recursion, requiring a deep understanding of data structures and algorithms.
Detailed Explanation
The problem can be solved by creating a recursive function that subtracts the given integer from each node in the linked list. The function should recursively traverse the list, subtracting the value from each node's value until it reaches the end of the list.
Here is the step-by-step breakdown of the solution:
- Create a new function
subtractthat takes the head of the linked list and the integer value as input. - If the head of the list is
NULL, returnNULL. - Subtract the given integer from the current node's value.
- Recursively call the
subtractfunction on the next node in the list. - Return the modified linked list.
The time complexity of this solution is O(n), where n is the number of nodes in the linked list, as each node is visited once. The space complexity is O(1), as only a constant amount of space is used to store the function's recursive calls.
Optimized Solutions
Java
public ListNode subtract(ListNode head, int val) {
if (head == null)
return null;
head.val -= val;
head.next = subtract(head.next, val);
return head;
}
class ListNode {
int val;
ListNode next;
ListNode(int x) { val = x; }
}