07
05/2015
[LeetCode] Remove Duplicates from Sorted List
Remove Duplicates from Sorted List
Given a sorted linked list, delete all duplicates such that each element appear only once.
For example,
Given 1->1->2, return 1->2.
Given 1->1->2->3->3, return 1->2->3.
解题思路：
链表的一般技巧就是增加一个伪头结点，然后在返回的时候删除伪头结点即可，这样就能减少不同情况的讨论。
/**
* 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) {
ListNode* myHead=new ListNode(0);
myHead->next = head;
ListNode *p=myHead, *q;
while(p->next!=NULL&&p->next->next!=NULL){
if(p->next->val == p->next->next->val){
q=p->next;
p->next = p->next->next;
delete q;
}else{
p=p->next;
}
}
p=myHead;
myHead=myHead->next;
delete p;
return myHead;
}
};二次刷题（2015-08-03）
/**
* 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){
return head;
}
ListNode* p = head, *q;
while(p->next!=NULL){
if(p->next->val == p->val){
q = p->next;
p->next = q->next;
delete q;
}else{
p=p->next;
}
}
return head;
}
};
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