83. 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.
題目大意：
去除有序鏈表內部相同元素，即相同元素只保留一個。
代碼如下：
/**
* 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 NULL;
ListNode* p = head->next;
ListNode* pre = head;
int cur = head->val;
while(p != NULL)
{
if(cur == p->val)
{
pre->next = p->next;
}
else
{
cur = p->val;
pre = p;
}
p = p->next;
}
return head;
}
};其他簡潔做法：
1.雙while
參考自：https://discuss.leetcode.com/topic/2168/concise-solution-and-memory-freeing
class Solution {
public:
ListNode *deleteDuplicates(ListNode *head) {
ListNode* cur = head;
while (cur) {
while (cur->next && cur->val == cur->next->val)
cur->next = cur->next->next;
cur = cur->next;
}
return head;
}
};2.雙指針
參考自：https://discuss.leetcode.com/topic/2168/concise-solution-and-memory-freeing
ListNode *deleteDuplicates(ListNode *head) {
ListNode*cur=head,*tail=head;
while(cur){
if(cur->val!=tail->val){
tail->next=cur;
tail=cur;
}
cur=cur->next;
tail->next=NULL;
}
return head;
}2016-08-12 12:37:15