Remove Duplicates from Sorted List II

Description

Given a sorted linked list, delete all nodes that have duplicate numbers, leaving only distinct numbers from the original list.

Example
Given 1->2->3->3->4->4->5, return 1->2->5.
Given 1->1->1->2->3, return 2->3.

Link

Lintcode_ladder

Method

1. x
2. x

Example

1. 1

/**
 * Definition of ListNode
 * class ListNode {
 * public:
 *     int val;
 *     ListNode *next;
 *     ListNode(int val) {
 *         this->val = val;
 *         this->next = NULL;
 *     }
 * }
 */
class Solution{
public:
    /**
     * @param head: The first node of linked list.
     * @return: head node
     */
    ListNode * deleteDuplicates(ListNode *head) {
        // write your code here
        if (!head) {
            return nullptr;
        }
        ListNode dummy(0);
        dummy.next = head;
        // ListNode* result = &dummy;
        ListNode* cur = &dummy;
        while (cur->next && cur->next->next) {
            if (cur->next->val == cur->next->next->val) {
                int val = cur->next->val;
                while (cur->next && cur->next->val == val) {
                    cur->next = cur->next->next;
                }
            } else {
                cur = cur->next;
            }
        }
        return dummy.next;
    }
};

Similar problems

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