Leetcode: Remove Duplicates from Sorted List II
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:要充分利用sorted的性质,如果是sorted的那么重复的元素是连接在一起的,实现细节要注意删除node和未删除node指针向后移动的不同。
class Solution { public: ListNode *deleteDuplicates(ListNode *head) { if(head == NULL || head->next == NULL) return head; int dup = INT_MAX; ListNode *dummy = new ListNode(-1); dummy->next = head; for(ListNode *prev = dummy, *p = head; p; p = prev->next){ if(p->val == dup){ prev->next = p->next; }else if(p->next && p->val == p->next->val){ dup = p->val; prev->next = p->next; }else prev = p; } return dummy->next; } };