0083-remove-duplicates-from-sorted-list.cpp

/*
83. Remove Duplicates from Sorted List

Submitted: November 26, 2024

Runtime: 0 ms (beats 100.00%)
Memory: 16.08 MB (beats 99.94%)
*/

/**
 * 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) {}
 * };
*/
classSolution {
public:
 ListNode* deleteDuplicates(ListNode* head) {
if (head == nullptr) returnnullptr; // empty list
if (head->next == nullptr) return head; // list with one item cannot have duplicates
 ListNode* p=head;
while (p != nullptr && p->next != nullptr) {
// while loop to account for multiple duplicates
while (p->next != nullptr && p->next->val == p->val) { // p->next and p have same value
 p->next=p->next->next; // remove the node which p->next formerly referred to
 }
 p = p->next;
 }
return head;
 }
};