Online Judege Demo. Currently support Python and Java.

Find the longest diameter of a m-ary tree.

Given an undirected graph, find out all the vertices when removed will make the graph disconnec

Given a 2D grid, each cell is either a zombie or a human. Zombies can turn adjacent (up/down/left/ri

Find critical connections in a data center...

Given an array of integers representing the value of coupons, return the minimum number of consecuti

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