Given a sorted linked list, delete all nodes that have duplicate numbers, leaving only distinct numbers from the original list.
For example,
Given 1->2->3->3->4->4->5, return 1->2->5.
Given 1->1->1->2->3, return 2->3.
Given 1->2->3->3->4->4->5, return 1->2->5.
Given 1->1->1->2->3, return 2->3.
当发现相邻node值一样,记录这个值,把下面和这个值相等的Node都删除。注意Null check。
public class Solution { //Time: O(n) Space: O(1) public ListNode deleteDuplicates(ListNode head) { if (head == null || head.next == null) { return head; } ListNode dummy = new ListNode(0); dummy.next = head; head = dummy; while (head.next != null) { if (head.next.next != null && head.next.val == head.next.next.val) { int val = head.next.val; while (head.next != null && head.next.val == val) { head.next = head.next.next; } } else { head = head.next; } } return dummy.next; } }
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