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.

Approach : The key to solve the problem is using the right loop condition and maintaining necessary pointers in each loop.

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/** * Definition for singly-linked list. * struct ListNode { * int val; * struct ListNode *next; * }; */ struct ListNode* deleteDuplicates(struct ListNode* head) { struct ListNode *cur, *_next; if(head == NULL || head->next == NULL){ return head; } cur = head; while(cur && cur->next){ //set the pointer of the current next to the next node if duplicate is found if(cur->val == cur->next->val){ _next = cur->next->next; free(cur->next); cur->next = _next; }else{ //else just move forward to next node cur = cur->next; } } return head; }