Remove Duplicates from Sorted List

Description

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

Example
Given 1->1->2, return 1->2.
Given 1->1->2->3->3, return 1->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(INT_MIN);
        ListNode* result = &dummy;
        ListNode* cur = result;
        cur->next = head;
        cur = cur->next;
        head = head->next;
        while (head) {
            if (cur->val != head->val) {
                cur->next = head;
                cur = cur->next;
            }
            head = head->next;
        }
        cur->next = nullptr;
        return result->next;
    }
};

Similar problems

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Tags

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