算法题 - 随笔分类(第13页) - Pickle

LeetCode - Binary Tree Level Order Traversal

摘要：层次遍历，深刻理解树和递归。/** * Definition for binary tree * public class TreeNode { * int val; * TreeNode left; * TreeNode right; * TreeNode(int... 阅读全文

posted @ 2015-04-25 22:42 Pickle 阅读(179) 评论(0) 推荐(0)

LeetCode - Symmetric Tree

摘要：关于镜像树的相关操作，利用递归可以很简单的解决问题。注意判断根节点是不是null/** * Definition for binary tree * public class TreeNode { * int val; * TreeNode left; * TreeNod... 阅读全文

posted @ 2015-04-25 21:32 Pickle 阅读(153) 评论(0) 推荐(0)

LeetCode - Rank Scores

摘要：对分数排序参考了网上的答案而且如果不Order by 有一个BUG就是如果表为空则什么都不输出包括null才是正确的。 # Write your MySQL query statement belowselect s.Score, count(rank.Score) as Rankfrom ... 阅读全文

posted @ 2015-04-20 23:30 Pickle 阅读(203) 评论(0) 推荐(0)

LeetCode - Nth Highest Salary

摘要：题目大概意思是要求找出第n高的Salary，直接写一个Function。作为一个SQL新手我学到了1.SQL中Function的写法和变量的定义，取值。2.limit查询分页的方法。在这个题目中limit n-1, 1是从n-1开始取出一条数据。这样说比较直观。CREATE FUNCTION ... 阅读全文

posted @ 2015-04-20 23:01 Pickle 阅读(220) 评论(0) 推荐(0)

LeetCode - Department Highest Salary

摘要：题目大概的意思是选出每个Department里工资最高的人的信息并组成相应的表信息有几个值得注意的地方：1）使用group by语句时，前面的select语句后面的内容只能有两种情况一种是group by后面的属性，另一种是聚集函数。 2）在选取最大Salary时必须使用e1.Salary=e... 阅读全文

posted @ 2015-04-20 22:22 Pickle 阅读(214) 评论(0) 推荐(0)

LeetCode - Rising Temperature

摘要：Description：Given a Weather table, write a SQL query to find all dates' Ids with higher temperature compared to its previous (yesterday's) dates. 选出比... 阅读全文

posted @ 2015-04-19 23:01 Pickle 阅读(283) 评论(0) 推荐(0)

LeetCode - Delete Duplicate Emails

摘要：Discription：Write a SQL query to delete all duplicate email entries in a table named Person, keeping only unique emails based on its smallest Id. 删除重... 阅读全文

posted @ 2015-04-19 22:16 Pickle 阅读(204) 评论(0) 推荐(0)

LeetCode - Customers Who Never Order

摘要：Description: Suppose that a website contains two tables, the Customers table and the Orders table. Write a SQL query to find all customers who never ... 阅读全文

posted @ 2015-04-19 21:55 Pickle 阅读(191) 评论(0) 推荐(0)

LeetCode - Duplicate Emails

摘要：Description：Write a SQL query to find all duplicate emails in a table named Person. 找出表中重复的Email。# Write your MySQL query statement belowselect Email... 阅读全文

posted @ 2015-04-18 09:02 Pickle 阅读(170) 评论(0) 推荐(0)

LeetCode - Employees Earning More Than Their Managers

摘要：Description：The Employee table holds all employees including their managers. Every employee has an Id, and there is also a column for the manager Id.G... 阅读全文

posted @ 2015-04-16 23:44 Pickle 阅读(214) 评论(0) 推荐(0)

LeetCode - Second Highest Salary

摘要：Description： Write a SQL query to get the second highest salary from the Employee table.+----+--------+| Id | Salary |+----+--------+| 1 | 100 ||... 阅读全文

posted @ 2015-04-16 23:17 Pickle 阅读(192) 评论(0) 推荐(0)

LeetCode - Combine Two Tables

摘要：Description：Write a SQL query for a report that provides the following information for each person in the Person table, regardless if there is an add... 阅读全文

posted @ 2015-04-16 22:48 Pickle 阅读(164) 评论(0) 推荐(0)

LeetCode - Same Tree

摘要：Description:Given two binary trees, write a function to check if they are equal or not. Two binary trees are considered equal if they are structurall... 阅读全文

posted @ 2015-04-12 22:20 Pickle 阅读(187) 评论(0) 推荐(0)

LeetCode - Merge Sorted Array

摘要：Description： Given two sorted integer arrays A and B, merge B into A as one sorted array. Note: You may assume that A has enough space (siz... 阅读全文

posted @ 2015-04-11 23:04 Pickle 阅读(167) 评论(0) 推荐(0)

LeetCode - Remove Duplicates from Sorted List

摘要：Description：Given a sorted linked list, delete all duplicates such that each element appear only once. For example, Given 1->1->2, return 1->2. Given... 阅读全文

posted @ 2015-04-11 22:31 Pickle 阅读(178) 评论(0) 推荐(0)

LeetCode - Climbing Stairs

摘要：Description： You are climbing a stair case. It takes n steps to reach to the top. Each time you can either climb 1 or 2 steps. In how many distinct wa... 阅读全文

posted @ 2015-04-11 11:33 Pickle 阅读(184) 评论(0) 推荐(0)

LeetCode - PlusOne

摘要：题意：给一个数按位存放在一个int数组中，要求返回这个数加一后的数组。懒人解法：public class Solution { public int[] plusOne(int[] digits) { java.math.BigInteger Bigdigits = new jav... 阅读全文

posted @ 2015-04-11 11:12 Pickle 阅读(207) 评论(0) 推荐(0)

LeetCode - Length of Last Word

摘要：Java的字符串也很强大。public class Solution { public int lengthOfLastWord(String s) { if(s.length() == 0) return 0; String[] str = s.trim(... 阅读全文

posted @ 2015-04-03 18:22 Pickle 阅读(138) 评论(0) 推荐(0)

LeetCode - Add Binary

摘要：Java对二进制的支持还是比较好的，用上BIgInteger连溢出都不用考虑了。public class Solution { public String addBinary(String a, String b) { java.math.BigInteger ia = new java.m... 阅读全文

posted @ 2015-04-03 18:20 Pickle 阅读(161) 评论(0) 推荐(0)

LeetCode - Valid Sudoku

摘要：判断是不是符合数独的规则。数独的规则：每一行每一列不能有重复的数字，每一个3X3方格中不能有重复的数字，但是这个题中可以为空即都是'.'。（要养成良好的编程习惯啊，要不一点低级错误不容易发现，浪费生命！）public class Solution { public boolean isVal... 阅读全文

posted @ 2015-04-03 14:09 Pickle 阅读(267) 评论(0) 推荐(0)

随笔分类 - 算法题

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