9、删除排序链表中的重复元素

[conan1992]

题目描述

给定一个排序链表，删除所有重复的元素，使得每个元素只出现一次。

示例 1:

输入: 1->1->2
输出: 1->2

示例 2:

输入: 1->1->2->3->3
输出: 1->2->3

/**
 * Definition for singly-linked list.
 * function ListNode(val) {
 *     this.val = val;
 *     this.next = null;
 * }
 */
/**
 * @param {ListNode} head
 * @return {ListNode}
 */
var deleteDuplicates = function(head) {
    let start = NaN;
    let ans = new ListNode();
    let next = head
    let result = ans
    while( next ){
        if( start != next.val ){
            start = next.val;
            result.next = new ListNode();
            result.next.val = start;
            result = result.next;
        }
        next = next.next;
    }
    return ans.next
};