3217. Delete Nodes from Linked List Present in Array

Problem Statement

3217. Delete Nodes From Linked List Present in Array

Medium

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.

Java

Source file

/**
 * Definition for singly-linked list.
 * public class ListNode {
 *     int val;
 *     ListNode next;
 *     ListNode() {}
 *     ListNode(int val) { this.val = val; }
 *     ListNode(int val, ListNode next) { this.val = val; this.next = next; }
 * }
 */
class Solution {
    public ListNode modifiedList(int[] nums, ListNode head) {
    Set<Integer> del = Arrays.stream(nums).boxed().collect(Collectors.toCollection(HashSet::new));
        ListNode curr = head, dummy = new ListNode(0, head), prev = dummy;
        while(curr!=null){
            while(curr!=null && del.contains(curr.val))
                curr = curr.next;
            prev.next = curr;
            if(curr==null)
                break;
            curr = curr.next;
            prev = prev.next;
        }
        return dummy.next;
    }
}