Leetcode203. 移除鏈表元素

刪除鏈表中等於給定值 val 的所有節點。

示例:

輸入: 1->2->6->3->4->5->6, val = 6
輸出: 1->2->3->4->5

# Definition for singly-linked list.
# class ListNode(object):
#     def __init__(self, x):
#         self.val = x
#         self.next = None

class Solution(object):
    def removeElements(self, head, val):
        """
        :type head: ListNode
        :type val: int
        :rtype: ListNode
        """
        if head == None : return None
        cur = head # 必須調用外部空間，否則head最後就會指向爲空
        
        while cur.next != None:
            if cur.next.val == val:
                cur.next = cur.next.next
            else:
                cur = cur.next
        
        return head if head.val !=val else head.next # 以防只剩最後一位但是是索引的數