2023.09.07 Today's Challenge

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

Reverse Linked List II - LeetCode

링크드리스트 문제

class Solution:
    def reverseBetween(self, head: Optional[ListNode], left: int, right: int) -> Optional[ListNode]:
        if not head or left == right:
            return head

        dummy = ListNode(0, head)
        prev = dummy

        for _ in range(left - 1):
            prev = prev.next

        current = prev.next

        for _ in range(right - left):
            next_node = current.next
            current.next, next_node.next, prev.next = next_node.next, prev.next, next_node
        
        return dummy.next