https://leetcode.com/problems/remove-duplicates-from-sorted-list/description/ 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.

1 public ListNode deleteDuplicates(ListNode head) { 2         if (head == null || head.next == null) return head ; 3         ListNode curr = head ; 4         /* 5         * 重点体会跳过去是什么意思 CURR =HEAD 然后改变 CURR.NEXT HEAD.next 也是会被变化的 6         * */ 7         /* 8         *  1-1-1-1-2-2-3 9         *  c--->10         *   ---->11         *   ------->12         *          c13         *  h------->14         * */15         while(curr.next!=null){16             if (curr.val == curr.next.val){17                 curr.next = curr.next.next ;18             } else {19                 curr = curr.next ;20             }21         }22         return head ;23     }