Reverse Linked List

01 · Question

Given the head of a singly linked list, reverse the list, and return the reversed list.

02 · Solution

Reference solution

1def reverseList(head: Optional[ListNode]) -> Optional[ListNode]:
2    prev = None
3    cur = head
4    
5    while cur:
6        nxt = cur.next
7        cur.next = prev
8        prev = cur
9        cur = nxt
10        
11    return prev

Merge Two Sorted Lists