链表仍然是我的老大难……总是过分关注于边界条件了。
/**
* Definition for singly-linked list.
* struct ListNode {
* int val;
* ListNode *next;
* ListNode(int x) : val(x), next(NULL) {}
* };
*/
class Solution {
public:
ListNode *deleteDuplicates(ListNode *head) {
if (head == NULL || head->next == NULL)
return head;
ListNode *fake_head = new ListNode(-1);
fake_head->next = head;
ListNode *last = fake_head, *p = head;
while (p != NULL && p->next != NULL) {
if (p->val == p->next->val) {
while (p->next != NULL && p->next->val == p->val)
p = p->next;
last->next = p->next;
p = p->next;
}
else {
last = p;
p = p->next;
}
}
head = fake_head->next;
delete fake_head;
return head;
}
};
http://oj.leetcode.com/problems/remove-duplicates-from-sorted-list-ii/