LeetCode有10道SQL的题目,最近学习SQL语言,顺便刷题强化一下, 说实话刷完SQL学习指南这本书,不是很难,上面的例子 跟语法规则我都能理解透, 实际中来做一些比较难的业务逻辑题,却一下子很难想起如何利用SQL来描述 还是要多刷题开阔自己的思路,把学到手的语法加以练习 应用到实际中去 197. Rising Temperature Given a Weather table, write a SQL query to find all dates' Ids with higher t…

LeetCode高频题目(100)汇总-Java实现       LeetCode高频题目(100)汇总-Java实现 目录 第01-50题 [Leetcode-easy-1] Two Sum [Leetcode-easy-2] Add Two Numbers [Leetcode-easy-3] Longest Substring Without Repeating Characters [Leetcode-easy-5] Longest Palindromic Substring [Leetc…

LeetCode算法题目解答汇总 本文转自<四火的唠叨> 只要不是特别忙或者特别不方便,最近一直保持着每天做几道算法题的规律,到后来随着难度的增加,每天做的题目越来越少.我的初衷就是练习,因为一方面我本身算法基础并不好,再一方面是因为工作以后传统意义上所谓算法的东西接触还是太少.为了题目查找方便起见,我把之前几篇陆陆续续贴出来的我对LeetCode上面算法题的解答汇总在下面,CTRL+F就可以比较方便地找到.由于LeetCode上的题在不断更新,因此我也会不定期地更新.下面表格里面的Accep…

LeetCode SQL题目 注意:Leetcode上的SQL编程题都提供了数据表的架构程序,只需要将它贴入本地数据库即可调试自己编写的程序 不管是MS-SQL Server还是MySQL都需要登陆才能使用,我没有使用SSMS 或Workbench,而是直接使用sqlcmd,解决登陆问题可以参考这个链接(http://www.cnblogs.com/skynothing/archive/2010/08/26/1809125.html)感谢这位博主的帮助. 181. Employees Earni…

leetcode二叉树题目总结 题目链接:https://leetcode-cn.com/leetbook/detail/data-structure-binary-tree/ 前序遍历(NLR) public List<Integer> preorderTraversal(TreeNode root) { List<Integer> res = new ArrayList<>(); preOrder(root, res); return res; } ​ public…

1.文字描述: 已知一颗二叉树的前序(后序)遍历序列和中序遍历序列,如何构建这棵二叉树? 以前序为例子: 前序遍历序列:ABCDEF 中序遍历序列:CBDAEF 前序遍历先访问根节点,因此前序遍历序列的第一个字母肯定就是根节点,即A是根节点:然后,由于中序遍历先访问左子树,再访问根节点,最后访问右子树,所以我们找到中序遍历中A的位置,然后A左边的字母就是左子树了,也就是CBD是根节点的左子树:同样的,得到EF为根节点的右子树. 将前序遍历序列分成BCD和EF,分别对左子树和右子树应用同样的方法,…

我会尽力将LeetCode上所有的题目都用动画的形式演示出来,期待与你见证这一天! GitHub Repo:LeetCode Animation Follow: MisterBooo · GitHub Problems ID Problem Article Animation 001 两数之和 每天一算:Two Sum 019 删除链表的倒数第N个节点 每天一算:Remove Nth Node From End of List 020 有效的括号 每天一算:Valid Parentheses 0…

题目链接:https://leetcode.com/problems/nth-highest-salary/description/ 题意:查询出表中工资第N高的值 思路: 1.先按照工资从高到低排序(注意去重) select distinct Salary from Employee order by Salary desc 2.使用rownum给查询出的数据标注行号 select rownum ro, s.Salary from (select distinct Salary from Em…

开源地址:点击该链接 前言 十月份共有60道题目,全部属于 Easy 难度的,所以公众号中分享出来的并不多,只是挑了一些感觉还可以的才分享了出来,这60道题目我按照不同类别进行了分类整理,所有源码以及对应的解题思路均匀开源到 GitHub,公众号内回复"LeetCode"获取,具体题目如下. 题目分类 数组 0001_two_sum 0026_remove_duplicates_from_sorted_array 0027_remove_element 0035_search_inse…

leetcode链表部分题目 https://zhuanlan.zhihu.com/p/29800285 <[Leetcode][链表]相关题目汇总/分析/总结> leetcode堆部分题目 https://www.cnblogs.com/zhangwanying/p/9357141.html <[LeetCode]堆 heap(共31题)> leetcode二叉树部分题目 https://blog.csdn.net/qqxx6661/article/details/7622347…

114,二叉树原地前序遍历转链表 令人不舒服的空间限制 4,O(logn)寻找两个数组的中位数 感觉诡异又很其妙的二分 279,判断一个数可拆成最少几个平方数的和 有O(n)解法,如果把sqrt视为O(1).因为有个定理,任何数都能拆成不超过4个平方数的和 O(1)判断一个行不行 O(sqrt(n))判断两个行不行 O(n)判断3个行不行 231,判断一个数是否是2的幂次 O(1), x&(x-1)=0 137,一个数组只有一个数出现一次,其他数都出现3次,找到这个数 时间O(n),空间O(1)…

Given a linked list, reverse the nodes of a linked list k at a time and return its modified list. If the number of nodes is not a multiple of k then left-out nodes in the end should remain as it is. You may not alter the values in the nodes, only nod…

1.Largest Rectangle in Histogram http://discuss.leetcode.com/questions/259/largest-rectangle-in-histogram http://www.cnblogs.com/remlostime/archive/2012/11/25/2787359.html 2.Minimum Window Substring http://discuss.leetcode.com/questions/97/minimum-wi…

心情还是有问题,保持每日更新,只能如此了. Problem Given a binary tree, return the level order traversal of its nodes' values. (ie, from left to right, level by level). Example: Given binary tree {,,,#,#,,}, ···· / \ / \ Result return its level order traversal as: [ [],…

Problem Given an integer, write a function to determine if it is a power of three. Follow up: Could you do it without using any loop / recursion? Code: class Solution { public: bool isPowerOfThree(int n) { if (n <= 0) return 0; int max_pow3 = log10(I…

175 Combine Two Tables 题目:左连接Person表和Address表. select FirstName,LastName,City,State from Person p left join Address a on p.PersonId=a.PersonId; 7个case耗时1001ms(注意耗时多次提交会不同,一般相差不大,偶尔也有相差大的)   --2015/1/11 176 Second Highest Salary 题目:写一条sql语句查询Employee …

Leetcode 92:反转链表II 解决这道题需要三个步骤: 找到需要反转的第一个节点.可以通过头节点前进m-1步,找到反转开始的位置. 将需要反转的部分进行反转.参考Leetcode 206:反转链表. 将反转部分与剩余部分进行链接.其中分为两种情况,m=1与m>1.当m=1时,仅需要将反转部分反转前的头节点的next指向反转部分反转前尾节点的后继,新链表的头节点为反转部分反转前的尾节点.当m>1时,还需要将反转部分反转前头节点的前驱的next指向反转部分反转前的末节点,新链表的头节点仍为…

一.Print in Order Suppose we have a class: public class Foo { public void first() { print("first"); } public void second() { print("second"); } public void third() { print("third"); } } The same instance of Foo will be passed…

Hello everyone, I am a Chinese noob programmer. I have practiced questions on leetcode.com for 2 years. During this time, I studied a lot from many Great Gods' articles. After worship, I always wanted to write an article as they did, and now I take t…

最近,新加坡总理李显龙也写了一份代码公布出来,大致瞧了一眼,竟然是解数独题的代码!前几天刚刚写过,数独主要算法当然是使用回溯法.回溯法当时初学的时候在思路上比较拧,不容易写对.写了几个回溯法的算法之后心里总算有了点底.回溯法的代码一般都是长成下面这样子: void backtracking(int[] arr, int boundary, int current, int[] result) { if(current>=boundary) //到达终止条件 { //判断result是否符合要求…

Write a 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 |…

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. In other words, there should be no "holes" be…

Consecutive Numbers Write a SQL query to find all numbers that appear at least three times consecutively. +----+-----+ | Id | Num | +----+-----+ | 1 | 1 | | 2 | 1 | | 3 | 1 | | 4 | 2 | | 5 | 1 | | 6 | 2 | | 7 | 2 | +----+-----+ For example, given the…

175. Combine Two Tables 使用外连接即可. # Write your MySQL query statement below select FirstName, LastName, City, State from Person left outer join Address on Person.PersonId = Address.PersonId; # Write your MySQL query statement below select p.FirstName,…

1. 第二高的薪水 select ifnull((select distinct Salary from Employee order by Salary desc limit 1,1),null) as SecondHighestSalary;   2.第N高的薪水 select distinct Salary from Employee e where N = (select count(distinct Salary) from Employee where Salary >= e.Sal…

Problem Given an integer (signed bits), write a function to check whether it . Example: Given num = , , return false. Follow up: Could you solve it without loops/recursion? Code class Solution { public: bool isPowerOfFour(int num) { ) && ((num &am…

本来打算写redis的,时间上有点没顾过来,只能是又拿出点自己的存货了. Problem Given an array nums, write a function to move all 's to the end of it while maintaining the relative order of the non-zero elements. Example: Given nums = [, , , , ], after calling your function, nums shou…

Problem: You are playing the following Nim Game with your friend: There is a heap of stones on the table, each time one of you take turns to remove 1 to 3 stones. The one who removes the last stone will be the winner. You will take the first turn to…

3.无重复字符的最长子串 /** * @param {string} s * @return {number} */ var lengthOfLongestSubstring = function(s) { var ans = [], vis = [], max = 0; for(var i = 0; i < 256; i++){ vis.push(-1); } for(var i = 0; i < s.length; i++){ var t = s[i].charCodeAt() - 0;…

X city built a new stadium, each day many people visit it and the stats are saved as these columns: id, date, people Please write a query to display the records which have 3 or more consecutive rows and the amount of people more than 100(inclusive).…