203. 移除链表元素

给你一个链表的头节点 head 和一个整数 val ，请你删除链表中所有满足 Node.val == val 的节点，并返回新的头节点。

示例 1：
输入：head = [1,2,6,3,4,5,6], val = 6
输出：[1,2,3,4,5]

示例 2：
输入：head = [], val = 1
输出：[]

示例 3：
输入：head = [7,7,7,7], val = 7
输出：[]

提示：
列表中的节点数目在范围 [0, 104] 内
1 <= Node.val <= 50
0 <= val <= 50

来源：力扣（LeetCode）
链接：https://leetcode.cn/problems/remove-linked-list-elements

javascript

/**
 * Definition for singly-linked list.
 * function ListNode(val, next) {
 *     this.val = (val===undefined ? 0 : val)
 *     this.next = (next===undefined ? null : next)
 * }
 */
/**
 * @param {ListNode} head
 * @param {number} val
 * @return {ListNode}
 */
var removeElements = function (head, val) {
  if (!head) return head
  if (head && !head.next) {
    if (head.val === val) {
      return null
    } else {
      return head
    }
  }
  var cur = head
  while (cur && cur.val === val) {
    cur = cur.next
    head = cur
  }
  if (cur === null) return null
  while (cur && cur.next) {
    if (cur.next.val === val) {
      cur.next = cur.next.next
    } else {
      cur = cur.next
    }
  }
  return head
}

// test
function ListNode(val, next) {
  this.val = val === undefined ? 0 : val
  this.next = next === undefined ? null : next
}

var n1 = new ListNode(1)
var n2 = new ListNode(2)
var n3 = new ListNode(6)
var n4 = new ListNode(3)
var n5 = new ListNode(4)
var n6 = new ListNode(5)
var n7 = new ListNode(6)
n1.next = n2
n2.next = n3
n3.next = n4
n4.next = n5
n5.next = n6
n6.next = n7

console.log(removeElements(n1, 6))

203. 移除链表元素 #

203. 移除链表元素