Robina Li

Given the root of a binary tree, invert the tree, and return its root.

You are given an array of strings words and a string pref.

Given a string s, return the length of the longest substring between two equal characters, excluding the two equal characters themselves. If no such substring exists, return -1.

Given the root of a binary tree and an integer targetSum, return true if the tree has a root-to-leaf path such that adding up all the values along the path...

Given a binary tree, find its minimum depth.

Given the root of a binary tree, return its maximum depth — the number of nodes along the longest path from the root down to the farthest leaf.

Given the root of a binary tree, check whether it is a mirror of itself (i.e., symmetric around its center).

Given the roots of two binary trees p and q, write a function to check if they are the same or not.

Design a data structure that supports adding new words and finding if a string matches any previously added string.

Given a string s which consists of lowercase or uppercase letters, return the length of the longest palindrome that can be built with those letters.