leetcode - 82. Remove Duplicates from Sorted List II

Description

Given the head of a sorted linked list, delete all nodes that have duplicate numbers, leaving only distinct numbers from the original list. Return the linked list sorted as well.

Example 1:

复制代码
Input: head = [1,2,3,3,4,4,5]
Output: [1,2,5]

Example 2:

复制代码
Input: head = [1,1,1,2,3]
Output: [2,3]

Constraints:

复制代码
The number of nodes in the list is in the range [0, 300].
-100 <= Node.val <= 100
The list is guaranteed to be sorted in ascending order.

Solution

Use a prev to record the previous node, and if the current node is duplicated by the next node, delete them. Otherwise move prev forward.

Time complexity: o ( n ) o(n) o(n)

Space complexity: o ( 1 ) o(1) o(1)

Code

python3 复制代码
# Definition for singly-linked list.
# class ListNode:
#     def __init__(self, val=0, next=None):
#         self.val = val
#         self.next = next
class Solution:
    def deleteDuplicates(self, head: Optional[ListNode]) -> Optional[ListNode]:
        ret_head = ListNode(-1)
        ret_head.next = head
        prev, p = ret_head, ret_head.next
        while p and p.next:
            pn = p.next
            need_delete = False
            while pn and pn.val == p.val:
                need_delete = True
                pn = pn.next
            if need_delete:
                prev.next = pn
                p = prev.next
            else:
                prev, p = prev.next, p.next
        return ret_head.next
相关推荐
孤廖几秒前
从 “模板” 到 “场景”,用 C++ 磨透拓扑排序的实战逻辑
开发语言·c++·程序人生·算法·贪心算法·动态规划·学习方法
Flash.kkl32 分钟前
优先算法——专题十一:字符串
算法
奔跑吧 android7 小时前
【linux kernel 常用数据结构和设计模式】【数据结构 2】【通过一个案例属性list、hlist、rbtree、xarray数据结构使用】
linux·数据结构·list·kernel·rbtree·hlist·xarray
汉克老师7 小时前
第十四届蓝桥杯青少组C++选拔赛[2023.2.12]第二部分编程题(5、机甲战士)
c++·算法·蓝桥杯·01背包·蓝桥杯c++·c++蓝桥杯
Mr_Xuhhh8 小时前
项目需求分析(2)
c++·算法·leetcode·log4j
c++bug9 小时前
六级第一关——下楼梯
算法
Morri39 小时前
[Java恶补day53] 45. 跳跃游戏Ⅱ
java·算法·leetcode
林木辛9 小时前
LeetCode热题 15.三数之和(双指针)
算法·leetcode·双指针
AndrewHZ9 小时前
【3D算法技术】blender中,在曲面上如何进行贴图?
算法·3d·blender·贴图·三维建模·三维重建·pcg
Jared_devin9 小时前
二叉树算法题—— [蓝桥杯 2019 省 AB] 完全二叉树的权值
数据结构·c++·算法·职场和发展·蓝桥杯