3217. Delete Nodes From Linked List Present in Array

Problem Link

Description

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You are given an array of integers nums and the head of a linked list. Return the head of the modified linked list after removing all nodes from the linked list that have a value that exists in nums.

 

Example 1:

Input: nums = [1,2,3], head = [1,2,3,4,5]

Output: [4,5]

Explanation:

Remove the nodes with values 1, 2, and 3.

Example 2:

Input: nums = [1], head = [1,2,1,2,1,2]

Output: [2,2,2]

Explanation:

Remove the nodes with value 1.

Example 3:

Input: nums = [5], head = [1,2,3,4]

Output: [1,2,3,4]

Explanation:

No node has value 5.

 

Constraints:

• 1 <= nums.length <= 105
• 1 <= nums[i] <= 105
• All elements in nums are unique.
• The number of nodes in the given list is in the range [1, 105].
• 1 <= Node.val <= 105
• The input is generated such that there is at least one node in the linked list that has a value not present in nums.

Solution

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Python3

# Definition for singly-linked list.
# class ListNode:
#     def __init__(self, val=0, next=None):
#         self.val = val
#         self.next = next
class Solution:
    def modifiedList(self, nums: List[int], head: Optional[ListNode]) -> Optional[ListNode]:
        s = set(nums)
        
        while head and head.val in s:
            head = head.next
        
        if not head: return None
 
        curr = head
 
        while curr.next:
            if curr.next.val in s:
                curr.next = curr.next.next
            else:
                curr = curr.next
 
        return head