Tag: oj online judge

You are a product manager and currently leading a team to develop a new product. Unfortunately, the latest version of your product fails the quality check. Since each version …

Regular Expressions (Regex) are very powerful and useful tool to describe patterns. https://leetcode.com/problems/valid-phone-numbers/ Given a text file file.txt that contains list of phone numbers (one per line), write a …

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 …

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) …