题目如下:

Given two sequences pushed and popped with distinct values, return true if and only if this could have been the result of a sequence of push and pop operations on an initially empty stack.

Example 1:

Input: pushed = [1,2,3,4,5], popped = [4,5,3,2,1]
Output: true
Explanation: We might do the following sequence:
push(1), push(2), push(3), push(4), pop() -> 4,
push(5), pop() -> 5, pop() -> 3, pop() -> 2, pop() -> 1

Example 2:

Input: pushed = [1,2,3,4,5], popped = [4,3,5,1,2]
Output: false
Explanation: 1 cannot be popped before 2.

Note:

  1. 0 <= pushed.length == popped.length <= 1000
  2. 0 <= pushed[i], popped[i] < 1000
  3. pushed is a permutation of popped.
  4. pushed and popped have distinct values.

解题思路:栈具有后进先出的特性,从这个特性中可以得出这么一个规律:对于出栈序列中的任意一个元素来说,在这个元素之前入栈的其他元素并且在这个元素之后出栈的这些元素必定满足后进先出。以 pushed = [8,2,1,4,7,9,0,3,5,6],popped = [1,2,7,3,6,4,0,9,5,8] 为例,对于元素3来说,在其之前入栈的元素为[8,2,1,4,7,9,0],在其后出栈的元素为[6,4,0,9,5,8] ,同时满足先于3入栈后于3出栈的元素为[8,4,9,0],这些元素出栈的顺序必定要满足[0,9,4,8]的顺序。所以只要遍历[8,4,9,0]序列,判断这些元素的在popped数组中的索引是否是递减即可。

代码如下:

class Solution(object):
def validateStackSequences(self, pushed, popped):
"""
:type pushed: List[int]
:type popped: List[int]
:rtype: bool
"""
dic_push = {}
dic_pop = {}
for i,v in enumerate(pushed):
dic_push[v] = i
for i, v in enumerate(popped):
dic_pop[v] = i for i,v in enumerate(popped):
push_inx = dic_push[v]
lastInx = len(popped)
for j in range(push_inx):
if dic_pop[pushed[j]] < i:
continue
elif dic_pop[pushed[j]] > lastInx :
return False
lastInx = dic_pop[pushed[j]]
return True

【leetcode】946. Validate Stack Sequences的更多相关文章

  1. 【LeetCode】946. Validate Stack Sequences 解题报告(Python & C++)

    作者: 负雪明烛 id: fuxuemingzhu 个人博客: http://fuxuemingzhu.cn/ 目录 题目描述 题目大意 解题方法 模拟过程 日期 题目地址:https://leetc ...

  2. Leetcode 946. Validate Stack Sequences 验证栈序列

    946. Validate Stack Sequences 题目描述 Given two sequences pushed and popped with distinct values, retur ...

  3. 946. Validate Stack Sequences

    946. Validate Stack Sequences class Solution { public: bool validateStackSequences(vector<int> ...

  4. 【LeetCode】468. Validate IP Address 解题报告(Python)

    [LeetCode]468. Validate IP Address 解题报告(Python) 标签(空格分隔): LeetCode 作者: 负雪明烛 id: fuxuemingzhu 个人博客: h ...

  5. (栈)leetcode 946. Validate Stack Sequences

    Given two sequences pushed and popped with distinct values, return true if and only if this could ha ...

  6. 946. Validate Stack Sequences验证栈序列

    网址:https://leetcode.com/problems/validate-stack-sequences/ 参考:https://leetcode.com/problems/validate ...

  7. 112th LeetCode Weekly Contest Validate Stack Sequences

    Given two sequences pushed and popped with distinct values, return true if and only if this could ha ...

  8. 【LeetCode】225. Implement Stack using Queues 解题报告(Python)

    作者: 负雪明烛 id: fuxuemingzhu 个人博客: http://fuxuemingzhu.cn/ 目录 题目描述 题目大意 解题方法 日期 题目地址:https://leetcode.c ...

  9. 【LeetCode】187. Repeated DNA Sequences 解题报告(Python)

    作者: 负雪明烛 id: fuxuemingzhu 个人博客: http://fuxuemingzhu.cn/ 题目地址: https://leetcode.com/problems/repeated ...

随机推荐

  1. $emit 和 $on 进行平行组件之间的传值

    效果图: 注:$emit 和 $on 的事件必须在一个公共的实例上,才能够触发: $emit 触发 $on 接收 需求: 1.有A.B.C三个组件,同时挂载到入口组件中: 2.将A组件中的数据传递到C ...

  2. RabbitMQ之交换机

    1. 交换机类型 rabbitmq常见有四种交换机类型: direct, topic, fanout, headers. 一般headers都不用,工作中用得较多的是fanout,它会将消息推送到所有 ...

  3. springBoot01-helloworld-完成一个简单的RESTful API

    1.访问http://start.spring.io/ 2.选择构建工具Maven Project.Spring Boot版本 2.0.1,以及一些工程基本信息 ,最后点击Generate Proje ...

  4. SpringMVC的 ModelAndView

    使用ModelAndView类用来存储处理完后的结果数据,以及显示该数据的视图. public class ModelAndView { /** View instance or view name ...

  5. JS中数据结构之字典

    字典是一种以键 - 值对形式存储数据的数据结构 通过数组实现字典 function Dictionary() { this.add = add; this.datastore = new Array( ...

  6. CSS中的一些伪类

    一.:nth-child 和 :nth-of-type (1):nth-child() :nth-child(n) 选择器选取某任意一父元素的第 n 个子元素( p:nth-child(n) 即选中任 ...

  7. flutter中的列表组件

    列表布局是我们项目开发中最常用的一种布局方式.Flutter 中我们可以通过 ListView 来定义列表项,支持垂直和水平方向展示.通过一个属性就可以控制列表的显示方向.列表有以下分类:  垂直列表 ...

  8. XX-net https://github.com/XX-net/XX-Net

    XX-net https://github.com/XX-net/XX-Net

  9. 三种数据库截取字段内容&&获取字符长度的函数如下

    if(databaseutil.getValue("database").equalsIgnoreCase("sqlserver")){ list =categ ...

  10. git配置密钥(私钥、ssh、公钥)

    参照: https://blog.csdn.net/weixin_42063071/article/details/80999690 经常帮人配置git的私钥,来总结一下简单的流程真心希望对大家有所帮 ...