Given an array of integers nums and an integer target, return indices of the two numbers such that they add up to target. You may assume that each input would have exactly one solution, and you may not use the same element twice. You can return the answer in any order.

Two Sum

Given an integer x, return true if x is a palindrome, and false otherwise. An integer is a palindrome when it reads the same backward as forward.

Palindrome Number

Write a SQL query to find all employees with a salary greater than 55000. Return name and salary columns, ordered by salary descending.

**Output columns (in order):** name, salary

**Table: employees**
| Column | Type |
|--------|------|
| id | INT |
| name | TEXT |
| salary | INT |

Employees With High Salary

Write a SQL query to find all duplicate emails in the users table. Return only the email column.

**Output columns (in order):** email

**Table: users**
| Column | Type |
|--------|------|
| id | INT |
| email | TEXT |

Find Duplicate Emails

Given an integer array nums, find the contiguous subarray (containing at least one number) which has the largest sum and return its sum.

Maximum Subarray

Given an integer array nums, return an array answer such that answer[i] is equal to the product of all the elements of nums except nums[i]. You must write an algorithm that runs in O(n) time and without using the division operation.

Product of Array Except Self

Write a SQL query to find the second highest salary from the employees table. If there is no second highest salary, return NULL.

**Output columns (in order):** salary (or NULL if not found)

**Table: employees**
| Column | Type |
|--------|------|
| id | INT |
| name | TEXT |
| salary | INT |

Second Highest Salary

Write a SQL query to find all numbers that appear at least three times consecutively in the logs table. Return distinct num.

**Output columns (in order):** num

**Table: logs**
| Column | Type |
|--------|------|
| id | INT |
| num | INT |

Consecutive Numbers

Given n non-negative integers representing an elevation map where the width of each bar is 1, compute how much water it can trap after raining.

Trapping Rain Water

Given two sorted arrays nums1 and nums2 of size m and n respectively, return the median of the two sorted arrays. The overall run time complexity should be O(log (m+n)).

Median of Two Sorted Arrays

Write a SQL query to find the median salary of all employees. Return the median salary. For an odd number of employees, return the middle value. For an even number, return the average of the two middle values.

**Output columns (in order):** median_salary

**Table: employee**
| Column | Type |
|--------|------|
| id | INT |
| salary | INT |

Find Median Salary

Write a SQL query to return the third highest distinct salary from the employees table as a single value named third_highest. If it does not exist, return null.

**Output columns (in order):** third_highest

**Table: employees**
| Column | Type |
|--------|------|
| id | INT |
| salary | INT |