Remove Duplicates from Sorted List II
Problem Statement - link #
Given the head of a sorted linked list, delete all duplicates such that each element appears only once. Return the linked list sorted as well.
Examples #
Example 1:
Input: head = [1,2,3,3,4,4,5]
Output: [1,2,5]
Example 2:
Input: head = [1,1,1,2,3]
Output: [2,3]
Constraints #
- The number of nodes in the list is in the range
[0, 300]. -100 <= Node.val <= 100- The list is guaranteed to be sorted in ascending order.
Solutions #
/**
* Definition for singly-linked list.
* struct ListNode {
* int val;
* ListNode *next;
* ListNode() : val(0), next(nullptr) {}
* ListNode(int x) : val(x), next(nullptr) {}
* ListNode(int x, ListNode *next) : val(x), next(next) {}
* };
*/
class Solution {
public:
ListNode* deleteDuplicates(ListNode* head) {
if(!head or !head->next) return head;
ListNode* t = new ListNode(-501);
t->next = head;
head = t;
while(t->next and t->next->next){
if(t->next->val == t->next->next->val){
ListNode* f = t->next;
while(f->next and f->val == f->next->val)
f = f->next;
t->next = f->next;
}
else t = t->next;
}
return head->next;
}
};