对于此类问题: 对于元素nums[i],找出往左/右走第一个比它小/大的数字 我们常常用递增栈/递减栈实现. 递增栈实现第一个比它小 递减栈实现第一个比它大 Example: 2 1 5 6 2 3 stack: 保证栈是递增的顺序,因此每个数进来之前先删除栈里比它大的数字. 因此每个数,当它被pop出来时,它在栈里的前一个元素是左边第一个比它小的数,将它pop出来的数是右边第一个比它小的数. (1) 2 (2) 1 (2被1pop出来,2左边第一个比它小的没有,右边第一个比它小的是1) (3)…

1. 原题链接:https://leetcode.com/problems/increasing-decreasing-string/ 2. 解题思路 直观的想法是:用有序map<char, int>记录字母和字母出现的次数 按照题目描述的方式,先顺序遍历map,再反序遍历map,直到map中的所有字母出现次数都为0为止 3. 算法 遍历字符串s,通过有序map<char, int>记录字母和字母出现的次数 设置标志forward表示当前是正向遍历map,还是反向遍历map 遍历m…

C. The Phone Number time limit per test 1 second memory limit per test 256 megabytes     Mrs. Smith is trying to contact her husband, John Smith, but she forgot the secret phone number! The only thing Mrs. Smith remembered was that any permutation of…

Contest 111 (题号941-944)(2019年1月19日,补充题解,主要是943题) 链接:https://leetcode.com/contest/weekly-contest-111 [941]Valid Mountain Array(第一题 3分)(google tag) 判断一个数组是不是 Mountain 数组. Mountain 数组的定义是 A.length >= 3There exists some i with 0 < i < A.length - 1 su…

I collect and make up this pseudocode from the book: <<Introduction to the Design and Analysis of Algorithms_Second Edition>> _ Anany LevitinNote that throughout the paper, we assume that inputs to algorithms fall within their specified ranges…

此课程(MOOCULUS-2 "Sequences and Series")由Ohio State University于2014年在Coursera平台讲授. PDF格式教材下载 Sequences and Series 本系列学习笔记PDF下载(Academia.edu) MOOCULUS-2 Solution Review Determine whether the series converges. 1. $\displaystyle\sum_{n=0}^{\infty}{n\…

An array is monotonic if it is either monotone increasing or monotone decreasing. An array A is monotone increasing if for all i <= j, A[i] <= A[j].  An array A is monotone decreasing if for all i <= j, A[i] >= A[j]. Return true if and only if…

n HBase world, RegionServer hotspotting is a common problem.  We can describe this problem with a single sentence: while writing records with sequential row keys allows the most efficient reading of data range given the start and stop keys, it causes…

Mrs. Smith is trying to contact her husband, John Smith, but she forgot the secret phone number! The only thing Mrs. Smith remembered was that any permutation of nn can be a secret phone number. Only those permutations that minimize secret value migh…

C. The Phone Number time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output Mrs. Smith is trying to contact her husband, John Smith, but she forgot the secret phone number! The only thing Mrs. Smit…