83. Remove Duplicates from Sorted List

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

Example 1:

Input: 1->1->2
Output: 1->2

Example 2:

Input: 1->1->2->3->3
Output: 1->2->3

去重，因为已经排序好，直接比较不同的结点的数据域放进去就行。

/**
 * Definition for singly-linked list.
 * struct ListNode {
 *     int val;
 *     struct ListNode *next;
 * };
 */
struct ListNode* deleteDuplicates(struct ListNode* head) {
    if(head==NULL)   return NULL;
    struct ListNode *current=head,*tail=head;
    while(current){
        if(current->val!=tail->val){
            tail->next=current; //符合条件的放到原本尾部的后面
            tail=current;       //让正确的成为新的尾部
        }
        current=current->next;
        tail->next=NULL;
    }
    return head;
}