[링크드 리스트] 링크드 리스트 뒤집기

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

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/**
 * Definition for singly-linked list.
 * public class ListNode {
 *     int val;
 *     ListNode next;
 *     ListNode() {}
 *     ListNode(int val) { this.val = val; }
 *     ListNode(int val, ListNode next) { this.val = val; this.next = next; }
 * }
 */
class Solution {
    public ListNode reverseBetween(ListNode head, int left, int right) {
        ListNode dummy = new ListNode(0);
        dummy.next = head;
        ListNode prev = dummy;

        for (int i=0; i<left-1;i++) {
            prev = prev.next;
        }
        ListNode curr = prev.next;

        for(int i=0; i<right-left; i++){
            ListNode forw = curr.next;
            curr.next = forw.next;
            forw.next = prev.next;
            prev.next = forw;
        }
        return dummy.next;
    }
}