北叶青藤

摘要： Given an array of integers A with even length, return true if and only if it is possible to reorder it such that A[2 * i + 1] = 2 * A[2 * i] for every 阅读全文

摘要： Whenever you expose a web service / api endpoint, you need to implement a rate limiter to prevent abuse of the service (DOS attacks). Implement a Rate 阅读全文

摘要： Design a logger system that receive stream of messages along with its timestamps, each message should be printed if and only if it is not printed in t 阅读全文

摘要： There is a ball in a maze with empty spaces and walls. The ball can go through empty spaces by rolling up, down, left or right, but it won't stop roll 阅读全文

摘要： Solve a given equation and return the value of x in the form of string "x=#value". The equation contains only '+', '-' operation, the variable x and i 阅读全文

摘要： We are given a list schedule of employees, which represents the working time for each employee. Each employee has a list of non-overlapping Intervals, 阅读全文

摘要： Serialization is the process of converting a data structure or object into a sequence of bits so that it can be stored in a file or memory buffer, or 阅读全文

摘要： Given a string, your task is to count how many palindromic substrings in this string. The substrings with different start indexes or end indexes are c 阅读全文

摘要： Given a binary tree, return all duplicate subtrees. For each kind of duplicate subtrees, you only need to return the root node of any one of them. Two 阅读全文

摘要： On a single threaded CPU, we execute some functions. Each function has a unique id between 0 and N-1. We store logs in timestamp order that describe w 阅读全文