82_javascript.js

// 给定一个排序链表，删除所有含有重复数字的节点，只保留原始链表中 没有重复出现 的数字。

// 示例 1:

// 输入: 1->2->3->3->4->4->5
// 输出: 1->2->5
// 示例 2:

// 输入: 1->1->1->2->3
// 输出: 2->3
/**
 * Definition for singly-linked list.
 * function ListNode(val) {
 *     this.val = val;
 *     this.next = null;
 * }
 */
/**
 * @param {ListNode} head
 * @return {ListNode}
 */
// 双指针
var deleteDuplicates = function (head) {
  if (!head || !head.next) {
    return head;
  }
  // 设定 temp
  let temp = new ListNode();
  temp.next = head;
  p = temp;
  let q = head;

  while (q && q.next) {
    if (p.next.val == q.next.val) {
      while (q.next && p.next.val == q.next.val) {
        q = q.next;
      }
      p.next = q.next;
      q = q.next;
    } else {
      q = q.next;
      p = p.next;
    }
  }
  return temp.next;
};
// 递归
var deleteDuplicates = function (head) {
  if (!head || !head.next) {
    return head;
  }
  let next = head.next;
  if (head.val == next.val) {
    while (next && head.val == next.val) {
      next = next.next;
    }
    head = deleteDuplicates(next);
  } else {
    head.next = deleteDuplicates(next);
  }
  return head;
};