小一的专栏

题目Given an integer n, count the total number of digit 1 appearing in all non-negative integers less than or equal to n.For example: Given n = 13, Return 6, because digit 1 occurred in the following n

目录目录前言题目DFS动态规划前言过完年回来状态一直就是懒懒散散的，之前想写的年终总结也一直再拖沓。所以，从今天起找回之前的状态，每日的工作计划没完成就不能休息。今天的任务中有两道LeetCode题目，其中一道动态规划的题目稍微难一点，这里记录一下解题过程。题目Given a string s and a dictionary of words di

目录目录前言题目思路1DFS思路2BFS前言最近这两天为了解决Android Rom适配一个底层的问题，天天熬夜到2点，导致原定了LeetCode刷题计划都受到了影响。昨晚终于熬夜搞定，补充一道LeetCode解题报告。题目Given a 2D board containing ‘X’ and ‘O’, capture all regions sur

目录目录题目思路1AC代码缺陷思路2AC代码题目 Design a stack that supports push, pop, top, and retrieving the minimum element in constant time. push(x) – Push element x onto stack. pop() – Removes the ele

目录目录题目题目Given two words (start and end), and a dictionary, find the length of shortest transformation sequence from start to end, such that:Only one letter can be changed at a time

题目    LeetCode题目如下：mplement an iterator over a binary search tree (BST). Your iterator will be initialized with the root node of a BST.Calling next() will return the next smallest number in the

题目Design and implement a data structure for Least Recently Used (LRU) cache. It should support the following operations: get and set.get(key) - Get the value (will always be positive) of the key

前言    今天来杭州参加百阿培训，住在4星级的旅馆，加上快一月底了我都没有几篇博客产出，所以准备开始水LeetCode题目了，这里介绍一个二分查找的应用。题目Suppose a sorted array is rotated at some pivot unknown to you beforehand.(i.e., 0 1 2 4 5 6 7 might become

题目Given an array S of n integers, are there elements a, b, c in S such that a + b + c = 0? Find all unique triplets in the array which gives the sum of zero.Note:Elements in a triplet (a,b,c)

题目Given a string S and a string T, count the number of distinct subsequences of T in S.A subsequence of a string is a new string which is formed from the original string by deleting some (can be

题目Determine whether an integer is a palindrome. Do this without extra space.click to show spoilers.Some hints:Could negative integers be palindromes? (ie, -1)If you are thinking of con

前言在LeetCode上又碰到了一道笔试原题，充分说明提前的准备对应届生找工作有多大的作用，年终总结我会具体写一下自己找工作的准备历程，耗时将近半年时间题目Given n non-negative integers representing an elevation map where the width of each bar is 1, compute how much w

前言新年第一篇博客先来一个解题报告吧，主要也是自己比较懒，跨年夜女友发烧各种照顾了，没来得及写年终总结，这篇解题报告也是我在做题过程中有些心得体会，跟大家分享！切忌心不静做题切忌杂乱无章，做题的时候想一下子处理所有特殊情况，结果越做约错在这里，先祝福各位看我博客的同学元旦快乐，万事如意题目Given a matrix of m x n ele

题目Given a string containing just the characters '(' and ')', find the length of the longest valid (well-formed) parentheses substring.For "(()", the longest valid parentheses substring is "()",

题目Given a binary tree, find the maximum path sum.The path may start and end at any node in the tree.For example:Given the below binary tree,

目录目录前言题目Native思路二进制思路AC前言最近在LeetCode上能一次AC的概率越来越低了，我这里也是把每次不能一次AC的题目记录下来，把解题思路分享给大家。题目All DNA is composed of a series of nucleotides abbreviated as A, C, G, and T, for example: “ACGAATTCCG”. When

目录目录题目思路AC代码题目 Given a list of non negative integers, arrange them such that they form the largest number. For example, given [3, 30, 34, 5, 9], the largest formed number is 9534330. Not

题目Given an array of n integers where n > 1, nums, return an array output such that output[i] is equal to the product of all the elements of nums except nums[i].Solve it without division and in O(n).For

前言难怪LeetCode OJ在找工作时被很多人推荐，发现了这道最大蓄水题目就是美团的笔试最后一道题，当时我霸笔只有着一道题目没有答出来，因此也就没有获得面试机会，可惜了题目Given n non-negative integers a1, a2, ..., an, where each represents a point at coordinate (i, ai). n v

目录目录思路思路AC代码思路Design a data structure that supports the following two operations: void addWord(word) bool search(word)search(word) can search a literal word or a regular expression string cont

目录目录概述Trie树基本实现定义Trie树节点添加操作查询word是否在Trie树中AC完整代码概述Trie树，又称为字典树、单词查找树或者前缀树，是一种用于快速检索的多叉数结构。例如，英文字母的字典树是26叉数，数字的字典树是10叉树。 Trie树的基本性质有三点，归纳为：根节点不包含字符，根节点外每一个节点都只包含一个字符。从根节点到某一节点，路径上经过的字符连接起来，为该节

题目There are a total of n courses you have to take, labeled from 0 to n - 1.Some courses may have prerequisites, for example to take course 0 you have to first take course 1, which is expressed as a pai

题目Write a SQL query to get the nth highest salary from the Employee table. Id Salary 1 100 2 200 3 300For example, given the above Employee table, the nth highest salary where n = 2 is

题目The Employee table holds all employees. Every employee has an Id, a salary, and there is also a column for the department Id. Id Name Salary DepartmentId 1 Joe 70000 1 2 Henry 80

题目Write a SQL query to rank scores. If there is a tie between two scores, both should have the same ranking. Note that after a tie, the next ranking number should be the next consecutive integer value.

题目SQL query to delete all duplicate email entries in a table named Person, keeping only unique emails based on its smallest Id. Id Email 1 john@example.com 2 bob@example.com 3 john@examp

目录目录前言题目思路AC代码我的疑问前言利用晚上11点之后的时间刷刷LeetCode也是我的一种休闲方式。不过水这篇博客是因为这道简单的BFS题目我竟然用了13次才AC，最后AC还是因为我参考了别人的答案，稍后我会说一下我对这道题的疑惑。先贴出这道题目我艰难的AC过程： 中间那次313ms的ac答案是我直接把别人的AC代码贴上，因为当时我怀疑这道题目答案是否出了问题。题目Given a

目录目录题目解题思路AC SQL题目Write a SQL query to find all duplicate emails in a table named Person. Id Email 1 a@b.com 2 c@d.com 3 a@b.comFor example, your query should return the following fo

目录目录题目思路AC SQL题目Given a Weather table, write a SQL query to find all dates’ Ids with higher temperature compared to its previous (yesterday’s) dates. Id(INT) Date(DATE) Temperature(INT) 1 2

目录目录题目思路AC SQL题目The Employee table holds all employees including their managers. Every employee has an Id, and there is also a column for the manager Id. Id Name Salary ManagerId 1 Joe

目录目录题目思路一思路二题目Given n non-negative integers representing the histogram’s bar height where the width of each bar is 1, find the area of largest rectangle in the histogram. Above is a histogram where

前言好久没有写关于ACM的博客了，确实是最近太忙，也怪我之前涉猎太少，i

题目Given a collection of intervals, merge all overlapping intervals.For example,Given [1,3],[2,6],[8,10],[15,18],return [1,6],[8,10],[15,18].解题思路题目不难，注意几点即可：1. Java的Comparator

前言回学校写论文差不多快一周的时间了，

前言这周末加上这星期的5天都需要帮导师做一个北邮烂尾的项目，很辛苦，不过知遇之恩确实太大，无以为报，只能竭心尽力无奈项目是用svn版本库控制，github的提交记录又多了一天空白，看着很不爽，哪天我不在github上提交代码，必然在svn上提交，嘿嘿题目Given an integer, convert it to a roman numeral.Input

前言今天上午从9点半开始就做了这么一道题目，还是挺有意思的，这里记录一下题目Follow up for problem "Populating Next Right Pointers in Each Node".What if the given tree could be any binary tree? Would your previous solution st

全组合例如给定字符串“abc”，全组合意思从中去0个元素，1个元素，一直到n个元素，介绍二进制做法。以字符串“abc”为例：000 NULL001 c010  b011  bc100  a101  ac110  ab111  abc思路出来了，代码也比较好写，分享一下我的代码：/** * Write a method that returns

前言今天准备把LeetCode上AC Rates在30%以上的题目全部收尾，这道题目也是我在这个AC Rate上遇到的感觉最麻烦的一道题目，分享一下自己的解题思路而且这道题目AC Rate竟然这么高题目Given n, how many structurally unique BST's (binary search trees) that

前言下午写LeetCode期间需要使用广度优先搜索算法，配合队列这种数据结构，队列数据结构的特性可以参考我之前的文章：队列的学习在java里使用队列可以用LinkedList集合进行模拟方法使用LinkedList集合，并使用其中的addLast、removeFirst、isEmpty等API集体模拟队列操作入队列void addLast(E

题目Given numRows, generate the first numRows of Pascal's triangle.For example, given numRows = 5,Return思路典型的杨辉三角题目，说一下构造杨辉三角的思路：每个数字等于上一行的左右两个数字之和。可用此性质写出整个杨辉三角。即第n+1行的第