206. Reverse Linked List

class Solution:
    def reverseList(self, head: Optional[ListNode]) -> Optional[ListNode]:
        prev, cur = None, head
        
        while cur:
            nex = cur.next
            cur.next = prev
            prev = cur
            cur = nex
        
        return prev

• use two pointers, starting prev before the start of the linked-list and cur at the first node.
• temporarily store the next node in a variable, flip the arrow, and then move the two pointers further along the list.

Categories:: linked-list, two-pointers