Remove Duplicates from Sorted List II

题目描写叙述

Given a sorted linked list, delete all nodes that have duplicate numbers, leaving only distinct numbers from the original list.

Example

Given 1->2->3->3->4->4->5, return 1->2->5.
Given 1->1->1->2->3, return 2->3.

链接地址

http://www.lintcode.com/en/problem/remove-duplicates-from-sorted-list-ii/

解法


ListNode * deleteDuplicates(ListNode *head) {
// write your code here
if (head == NULL) {
return head;
}
ListNode *dummyNode = new ListNode();
dummyNode->next = head;
ListNode *pre = dummyNode;
ListNode *cur = pre->next;
while (cur!= NULL && cur->next!= NULL) {
if (cur->val == cur->next->val) {
ListNode *temp = cur;
while (temp != NULL && temp->next != NULL && temp->val == temp->next->val) {
ListNode *del = temp->next;
temp->next = del->next;
delete del;
}
pre ->next = temp->next;
cur = pre->next;
delete temp;
} else {
pre = cur;
cur = cur->next;
}
}
ListNode *ret = dummyNode->next;
delete dummyNode;
return ret;
}