5.2.4.1 Remove Duplicates from Sorted List

一、题目

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.

给定一个排序链表，删除所有重复的元素每个元素只留下一个。

二、解题思路

遍历之，遇到当前节点和下一节点的值相同时，删除下一节点，并将当前节点next值指向下一个节点的next, 当前节点首先保持不变，直到相邻节点的值不等时才移动到下一节点。

三、解题代码

/**
 * Definition for ListNode
 * public class ListNode {
 *     int val;
 *     ListNode next;
 *     ListNode(int x) {
 *         val = x;
 *         next = null;
 *     }
 * }
 */
public class Solution {
    /**
     * @param ListNode head is the head of the linked list
     * @return: ListNode head of linked list
     */
    public static ListNode deleteDuplicates(ListNode head) {
        ListNode curr = head;
        while (curr != null) {
            while (curr.next != null && curr.val == curr.next.val) {
                curr.next = curr.next.next;
            }
            curr = curr.next;
        }

        return head;
    }
}