Robina Li

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.

A trie (pronounced as “try”) or prefix tree is a tree data structure used to efficiently store and retrieve keys in a dataset of strings. There are various applications of...

A k-booking happens when k events have some non-empty intersection (i.e., there is some time that is common to all k events).

You are given a string s. The score of a string is defined as the sum of the absolute difference between the ASCII values of adjacent characters.