[数据结构与算法]JZ56 删除链表中重复的结点 python

JZ56 删除链表中重复的结点

错误记录

1. 1->1->2 头节点可能被删除
2. 1->1->2->2
3. 1->1->2->3->3->4->5->5

class Solution:
    def find_no_repeat(self, node):
        p = node
        if p and p.next:
            if p.val != p.next.val:
                return p
            p_no_re = p.next
            while p_no_re and p.val == p_no_re.val:
                p_no_re = p_no_re.next
            return p_no_re
        else:
            return p
    def deleteDuplication(self, pHead):
        # 找到第一个不重复的节点
        p = self.find_no_repeat(pHead)
        while p and p != self.find_no_repeat(p):
            p = self.find_no_repeat(p)
        pHead = p
        while p:
            p_no_re = self.find_no_repeat(p.next)
            while p_no_re and p.next != p_no_re:
                p.next = p_no_re
                p_no_re = self.find_no_repeat(p.next)
            p.next = p_no_re
            p = p_no_re
        return pHead

book method
若当前节点是重复节点，则需将上一个节点的next与比当前节点值大的节点相连

class Solution:
    def deleteDuplication(self, pHead):
        # write code here
        newhead = ListNode('a')
        newhead.next = pHead
        pre, cur = None, newhead
        while cur:
            pre = cur
            cur = cur.next
            #判断指针的下一个值是否与当前值相等
            while cur and cur.next and cur.val == cur.next.val:
                t = cur.val
                #和当前值t相等的结点都被抛弃
                while cur and t == cur.val:
                    cur = cur.next
                pre.next = cur
        return newhead.next