203_移除链表元素

类型：链表

• 203. 移除链表元素 💚

  https://leetcode-cn.com/problems/remove-linked-list-elements/

  ❓ 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。返回完成删除后的链表结点。

  💡 一次遍历

  class Solution:
      def removeElements(self, head: ListNode, val: int) -> ListNode:
          while head and head.val == val:
              head = head.next
          node = head
          while node:
              if node.next and node.next.val == val:
                  node.next = node.next.next
              else:
                  node = node.next
          return head

  class Solution:
      def removeElements(self, head: ListNode, val: int) -> ListNode:
          while head and head.val == val:
              head = head.next
          slowNode = head
          while slowNode:
              if slowNode.next and slowNode.next.val == val:
                  fastNode = slowNode.next
                  while fastNode.next and fastNode.next.val == val:
                      fastNode = fastNode.next
                  slowNode.next = fastNode.next
              else:
                  slowNode = slowNode.next
          return head

  时间复杂度：O(n)，空间复杂度：O(1)