描述

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.

分析

无

代码

1 public static ListNode deleteDuplicates2(ListNode head) { 2         if (head == null || head.next == null)  3             return head; 4          5         int t = Integer.MIN_VALUE; 6         ListNode fakehead = new ListNode(t);// 加了个头指针 7         fakehead.next = head; 8         ListNode ptr0 = fakehead; 9         ListNode ptr1 = fakehead.next;10         ListNode ptr2 = fakehead.next.next;11         boolean flag = false;12         while (ptr2 != null) {13             if (ptr1.data == ptr2.data) {14                 flag = true;15                 ptr2 = ptr2.next;16                 ptr1 = ptr1.next;17                 if (ptr2 == null)18                     ptr0.next = null;19             } else {20                 if (flag) {21                     ptr0.next = ptr2;22                     flag = false;23                     ptr1 = ptr2;24                     ptr2 = ptr2.next;25                 } else {26                     ptr0 = ptr0.next;27                     ptr1 = ptr2;28                     ptr2 = ptr2.next;29                 }30             }31         }32         return fakehead.next;33     }