快乐的LeetCode --- 83. 删除排序链表中的重复元素

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

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解题思路1:

类似题解：面试题18. 删除链表的节点

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代码1： 超出时间限制

# Definition for singly-linked list.
# class ListNode(object):
#     def __init__(self, x):
#         self.val = x
#         self.next = None

class Solution(object):
    def deleteDuplicates(self, head):
        pre, cur = head, head.next
        while pre and cur:
            if pre.val == cur.val:
                pre.next = cur.next
            else:
                pre, cur = cur, cur.next

        return head

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解题思路2:

类似题解：面试题18. 删除链表的节点

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代码2：

写法1：

# class ListNode(object):
#     def __init__(self, x):
#         self.val = x
#         self.next = None

class Solution(object):
    def deleteDuplicates(self, head):
        res = head
        while res and res.next:
            if res.val == res.next.val:
                res.next = res.next.next 
            else:
                res = res.next
        return head

写法2：

# class ListNode(object):
#     def __init__(self, x):
#         self.val = x
#         self.next = None

class Solution(object):
    def deleteDuplicates(self, head):
        if not head: return None
        pre, cur = head, head.next
        while pre and cur:
            if pre.val == cur.val:
                pre.next = cur.next
                cur = cur.next
            else:
                pre, cur = cur, cur.next
        return head

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C++写法：

/**
 * Definition for singly-linked list.
 * struct ListNode {
 *     int val;
 *     ListNode *next;
 *     ListNode(int x) : val(x), next(NULL) {}
 * };
 */
class Solution {
public:
    ListNode* deleteDuplicates(ListNode* head) {
        auto cur = head;
        while(cur){
            if (cur -> next && cur -> next -> val == cur -> val)
                cur -> next = cur -> next -> next;
            else
                cur = cur -> next;
        }
        return head;
    }
};

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参考链接:

面试题18. 删除链表的节点

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题目来源：

https://leetcode-cn.com/problems/remove-duplicates-from-sorted-list

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同类题目：

[1]. 面试题18. 删除链表的节点
[2]. 237. 删除链表中的节点
[3]. 876. 链表的中间结点