Online Judege Demo. Currently support Python and Java.

Given a string str and an integer k, you need to rearrange the string in a way that the same charact

Implement the following class to keep track of the first unique number in a data stream.

Given the bank currency exchange rate table, find out the best currency exchange rate from currency

Given the bank currency exchange rate table, find out if it’s possible to exchange from currency .

Given a two 2D integer array, find the max score of a path from the upper left corner to bottom righ

Given a two 2D integer array, find the max score of a path from the upper left corner to bottom righ

Given a n*n 2D array. Fill the integer from 1 to n*n to this 2D array that makes the sum of each

Given a M-ary tree, find the subtree with maximum average. Return the root of the subtree.

Given a BST, and an integer k, cut the BST vertically into two substrees A and B, where all nodes in

A pizza shop offers n pizzas along with m toppings. A customer plans to spend around x coins. The cu

Given a binary tree and a list of nodes say [n1, n2, .. nk], write a program to find the least comm

You are given a huge number of IPs in a list. Remove all duplicated addresses from the list.

Given an int n, return all possible representations of n in Fibonacci base.

Design and implement the Least Recently Used Cache with TTL(Time To Live)