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, determine if it is height-balanced. A height-balanced binary tree is one in which the depth of the two subtrees of every node never differs by more...

Given an integer array nums of unique elements, return all possible subsets (the power set). The solution must not contain duplicate subsets.

Given an integer array nums and an integer k, return true if nums has a good subarray, i.e., a contiguous subarray of length at least 2 whose sum is a...

Design a Tic-Tac-Toe game that is played on an n x n board between two players. A move is guaranteed to be valid and is placed on an empty block....

Given two numbers hour and minutes, return the smaller angle (in degrees) formed between the hour and the minute hand of a clock.

Tic-tac-toe is played on a 3 x 3 grid by two players A and B. Player A always plays first. Given an array moves where moves[i] = [row, col] indicates...

Given a positive integer n, generate an n × n matrix filled with elements from 1 to n² in spiral order (clockwise).

Given two non-negative integers represented as strings num1 and num2, return their product as a string. You cannot convert the inputs to integers directly (numbers can be very large).

Given n non-negative integers representing an elevation map where the width of each bar is 1, compute how much water it can trap after raining.