#7EasyLinked Lists· Pointer Reversal

Reverse Linked List

Given the `head` of a singly linked list, reverse the list so that the last node becomes the first, and return the new head. Rewire the existing nodes' `next` pointers instead of creating new nodes. In the examples and tests the list is written as an array of node values from head to tail; an empty array means `head` is null.

Input format

head: array of integers representing the list from head to tail (may be empty)

Output format

Array of integers: the reversed list from its new head to its tail

Examples

Input: head = [1, 2, 3, 4, 5]

Output: [5, 4, 3, 2, 1]

Every pointer is flipped, so 5 becomes the new head.

Input: head = []

Output: []

An empty list stays empty.

Constraints

0 <= number of nodes <= 5000
-5000 <= Node.val <= 5000

Study first

Linked Lists & Pointer Nodes

#linked-lists
#pointers
#iteration