83. Remove Duplicates from Sorted List

Given a sorted linked list, delete all duplicates such that each element appear only once.

Example 1:

Input: 1->1->2
Output: 1->2

Example 2:

Input: 1->1->2->3->3
Output: 1->2->3

ListNode* deleteDuplicates(ListNode* head) { // time: O(n); space: O(1)
    ListNode* cur = head;
    while (cur && cur->next) {
        if (cur->val == cur->next->val) {
            ListNode *nodeToDel = cur->next;
            cur->next = cur->next->next;
            delete nodeToDel;
        } else {
            cur = cur->next;
        }
    }
    return head;
}