LeetCode第83题解析

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

解题思路：

迭代：

class Solution {
public:
    ListNode* deleteDuplicates(ListNode* head) {
        ListNode* cur = head;
        while(cur != NULL && cur->next != NULL) {
            if(cur->next->val == cur->val) {
                cur->next = cur->next->next;
            }
            else {
                cur = cur->next;
            }
        }
        return head;
    }
};

递归：

class Solution {
public:
    ListNode* deleteDuplicates(ListNode* head) {
        //terminator
        if(head == NULL || head->next == NULL) {
            return head;
        }
        head->next = deleteDuplicates(head->next);
        if(head->val == head->next->val) {
            head = head->next;
        }
        return head;
    }
};