Given the head of a linked list and an integer val, remove all the nodes of the linked list that has Node.val == val, and return the new head.
Example1:
Input: head = [1,2,6,3,4,5,6], val = 6 Output: [1,2,3,4,5]
Example2:
Input: head = [], val = 1 Output: []
Example3:
Input: head = [7,7,7,7], val = 7 Output: []
这道题没有什么算法,就是在写list的时候注意边界条件。多多练习,就算题目简单,刚开始也会有很多错误。
/** * 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 removeElements(ListNode head, int val) { if (head == null) { return null; } ListNode dummy = new ListNode(0, head); ListNode next = head; head = dummy; while (next != null) { while (next != null && next.val == val) { next = next.next; } head.next = next; if (next != null) { next = next.next; head = head.next; } } return dummy.next; } }