Reverse Linked List

Easy Subject: Linked List

Time Complexity

O(N)

Space Complexity

O(1)

Problem Description

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

Optimal Solution

Python

def reverseList(head):
    prev = None
    curr = head
    while curr:
        nxt = curr.next
        curr.next = prev
        prev = curr
        curr = nxt
    return prev