82. 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.注意保存链表头*//** * Definition for singly-linked list. * struct ListNode { *     int val; *     struct ListNode *next; * }; */struct ListNode* deleteDuplicates(struct ListNode* head){if(!head || !head->next) return head;    int val=head->val;struct ListNode *tmp=head->next;if(tmp->val != val){head->next=deleteDuplicates(tmp);return head;}else{while(tmp && tmp->val==val) tmp=tmp->next;return deleteDuplicates(tmp);}}struct ListNode* deleteDuplicates(struct ListNode* head){if(!head || !head->next) return head;    struct ListNode **h=&head;struct ListNode *fast=NULL;while(*h){fast=*h;if(fast->next && (*h)->val == fast->next->val){while(fast && (*h)->val == fast->val)fast=fast->next;*h=fast;}elseh=&((*h)->next);}return head;}