Understanding

Given the root node of a binary search tree (BST) and a value. You need to find the node in the BST that the node’s value equals the given value. Return the subtree rooted with that node. If such node doesn’t exist, you should return NULL. [Read More]

In a given grid, each cell can have one of three values: [Read More]

点评: ★★★★★ [Read More]

In a binary tree, the root node is at depth 0, and children of each depth k node are at depth k+1. [Read More]

Given an undirected graph, return true if and only if it is bipartite. [Read More]

Given a n-ary tree, find its maximum depth. [Read More]