LeetCode---83. Remove Duplicates from Sorted List

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

# 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):
        """
        :type head: ListNode
        :rtype: ListNode
        """
        if head and head.next:    #对于两个节点及以上的链表
            p = head
            while head.next:        #遇到两个相同值得结点删除后一个
                if head.val == head.next.val:
                    prv = head.next.next
                    head.next = prv
                else:
                    head = head.next
            return p
        else:                    #单节点链表或空链表直接返回头结点
            return head