LeetCode17|删除链表的节点

输入: head = [4,5,1,9], val = 5
输出: [4,1,9]
解释: 给定你链表中值为 5 的第二个节点，那么在调用了你的函数之后，该链表应变为 4 -> 1 -> 9.

import java.util.HashSet;
import java.util.LinkedHashSet;

public class DeleteNodeTest {
    public static void main(String[] args) {
        ListNode l1 = new ListNode(4);
        ListNode l12 = new ListNode(5);
        ListNode l13 = new ListNode(1);
        ListNode l14 = new ListNode(9);
        l1.next = l12;
        l12.next = l13;
        l13.next = l14;

        int val = 5;
        ListNode listNode = deleteNode(l1, val);
        System.out.println("listNode = " + listNode);
    }

    public static ListNode deleteNode(ListNode head, int val) {
        if (head == null) {
            return head;
        }
        HashSet<Integer> hashSet = new LinkedHashSet<>();
        ListNode temp = head;
        while (temp != null) {
            if (temp.val != val) {
                hashSet.add(temp.val);
            }
            temp = temp.next;
        }
        ListNode dummyNode = new ListNode(-1);
        ListNode tempNode = dummyNode;
        for (Integer num : hashSet
        ) {
            tempNode.next = new ListNode(num);
            tempNode = tempNode.next;
        }
        return dummyNode.next;
    }
}