83. Remove Duplicates from Sorted List

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

Example 1:

Input: 1->1->2
Output: 1->2

Example 2:

Input: 1->1->2->3->3
Output: 1->2->3
以为简单结果一下还没做出来，逻辑太差

/**
 * Definition for singly-linked list.
 * public class ListNode {
 *     int val;
 *     ListNode next;
 *     ListNode(int x) { val = x; }
 * }
 */
class Solution {
    public ListNode deleteDuplicates(ListNode head) {
       
        ListNode cur = head;
        while(cur!= null && cur.next != null){//细节，必须先判断cur
            if(cur.val == cur.next.val){
                cur.next = cur.next.next;
            }
            else{
                cur = cur.next;
            }
        }
        return head;
    }
}

class Solution {
    public ListNode deleteDuplicates(ListNode head) {
        if(head == null) return null;
        for(ListNode prev = head, cur = prev.next; cur != null; cur = prev.next){
            if(prev.val == cur.val){
                prev.next = cur.next;
            }
            else    prev = cur;
        }
        return head;
    }
}

另一种迭代，更好懂。cur一直等于prev的next，用prev来判断后面的是否有重复。