【Leetcode】83. Remove Duplicates from Sorted List

Question：

Given a sorted linked list, delete all duplicates such that each element appear only once.

For example,
Given 1->1->2, return 1->2.
Given 1->1->2->3->3, return 1->2->3.

Tips：將一個有序連結串列中的重複val的結點刪除。

思路：

設定一個指標，當指標下一個結點的val值與當前指標val相等就指標指向下一個結點的下一個。

cur.next=cur.next.next;

程式碼：

public ListNode deleteDuplicates(ListNode head) {
        if (head == null || head.next == null)
            return head;
        ListNode cur = head;
        while (cur != null) {
            if(cur.next!=null){
                if (cur.val == cur.next.val) {
                    cur.next=cur.next.next;
                }else{
                    cur=cur.next;
                }
            }else break;
        }
        return head;
    }

遞迴：

public ListNode deleteDuplicates2(ListNode head) {
        if (head == null || head.next == null)
            return head;
        head.next  =deleteDuplicates2(head.next);
        return head.val==head.next.val?head.next:head;
    }