Ruizhi Ma's Blog

Keep Calm and Carry On

Problem 176

Second Highest Salary

问题描述 https://leetcode.com/problems/second-highest-salary/ 解决思路 先找到最高的，再找到比最高的低的，就是第二高的Salary了 代码 # Write your MySQL query statement below Select max(Salary) as SecondHighestSalary From Employee W...

Posted by Ruizhi Ma on July 3, 2019

Problem 168

Excel Sheet Column Title

问题描述 Given a positive integer, return its corresponding column title as appear in an Excel sheet. For example: 1 -> A 2 -> B 3 -> C ... 26 -> Z 27 -> AA 28 -> AB ... Example 1:...

Posted by Ruizhi Ma on July 3, 2019

Problem 197

Rising Temperature

问题描述 https://leetcode.com/problems/rising-temperature/ 代码 # Write your MySQL query statement below SELECT tb1.Id FROM Weather as tb1 INNER JOIN Weather as tb2 ON tb1.Temperature > tb2.Temperatu...

Posted by Ruizhi Ma on July 3, 2019

Problem 155

Min Stack

问题描述 看链接：https://leetcode.com/problems/min-stack/ 解决思路 MinStack，就是创建另一个stack2，用来和push进stack1的元素比较，更小的一个，放入stack2，这样总能保证stack2的栈顶元素，是最小的 代码 package leetcode; import com.sun.corba.se.impl.orbutil....

Posted by Ruizhi Ma on July 2, 2019

Problem 181

Employee earning more than their manager

问题描述 https://leetcode.com/problems/employees-earning-more-than-their-managers/ 代码 # Write your MySQL query statement below SELECT tb1.Name as Employee FROM Employee as tb1 LEFT JOIN Employee as tb...

Posted by Ruizhi Ma on July 1, 2019

Problem 175

Combine two tables

问题描述 https://leetcode.com/problems/combine-two-tables/ 解决思路 用left join的方式，以tb1.PersonID = tb2.PersonID为条件，将两表join到一起，并且select出特定的行即可。 代码 # Write your MySQL query statement below SELECT tb1.FirstN...

Posted by Ruizhi Ma on July 1, 2019

Problem 160

Intersection of Two Linked Lists

问题描述 https://leetcode.com/problems/intersection-of-two-linked-lists/ 解决思路 身体不舒服，明天来补 问题解惑 代码 package leetcode; public class IntersectionofTwoLinkedLists { public class ListNode { int ...

Posted by Ruizhi Ma on July 1, 2019

Problem 69

Sqrt(x)

问题描述 Implement int sqrt(int x). Compute and return the square root of x, where x is guaranteed to be a non-negative integer. Since the return type is an integer, the decimal digits are truncated ...

Posted by Ruizhi Ma on June 30, 2019

TreeMap

TreeMap的使用和底层实现_Comparable接口

TreeMap类 package cn.sxt.collection; import java.util.Map; import java.util.TreeMap; /** * 测试TreeMap的使用 * @author Administrator * */ public class TestTreeMap { public static void main(String...

Posted by Ruizhi Ma on June 30, 2019

Problem 141

Linked List Cycle

问题描述 见链接：https://leetcode.com/problems/linked-list-cycle/ 解决思路 用两个快慢指针，快指针走到null就没有环，快指正走一次，慢指针走一次，相遇则有环。 问题解惑 好像在fast和slow走的地方有点模糊，因为slow和fast一起走，如果slow.next走过了fast.next城环的地方又当如何呢？(待解决) 代码 pack...

Posted by Ruizhi Ma on June 29, 2019

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