Reverse Linked List

LeetCode: https://leetcode.com/problems/reverse-linked-list/

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

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

cur

prevIdx=null

reversed=[]

remaining=[1, 2, 3, 4, 5]

Step 1 / 6

Step 1:

Initialize prev=nil, cur=head. No links reversed yet.

Pointers: cur=0

Focus: select @ [0]