Leetcode 92206：反转链表-反转链表 II

Posted 2021-12-18 hello，是翠花呀

反转链表 II

var reverseBetween = function (head, left, right) 
  let cur = head;
  let pre = null;
  let i = 1;

  if (left === right) 
    return head;
  

  while (i < left) 
    pre = cur;
    cur = cur.next;
    i++;
  

  let newCur = cur;
  let newPre = pre;

  while (i >= left && i <= right) 
    let next = cur.next;
    cur.next = pre;
    pre = cur;
    cur = next;

    i++;
  

  newCur.next = cur;
    if (newPre) 
      newPre.next = pre;
     else 
      head = pre;
    

  return head;
;

反转链表

var reverseList = function (head)  
  let cur = head
  let pre = null

  while(cur !== null) 
    let next = cur.next
    cur.next = pre
    pre = cur
    cur = next
  

  return pre