We have two special characters. The first character can be represented by one bit 0. The second character can be represented by two bits (10 or 11). N ...

The gray code is a binary numeral system where two successive values differ in only one bit. Given a non-negative integer n representing the total num ...

Given an array of strings, group anagrams together. ExampleInput: [“eat”, “tea”, “tan”, “ate”, “nat”, “bat”], Output: 12345[ ["ate","eat","tea"], [" ...

Given two non-negative integers num1 and num2 represented as strings, return the product of num1 and num2, also represented as a string. ExampleNo.1In ...

Given two non-negative integers num1 and num2 represented as string, return the sum of num1 and num2. Note The length of both num1 and num2 is < 51 ...

You are given an n x n 2D matrix representing an image. Rotate the image by 90 degrees (clockwise). Note: You have to rotate the image in-place, which ...

Given an array of integers nums sorted in ascending order, find the starting and ending position of a given target value. Your algorithm’s runtime com ...

Given an integer n, generate all structurally unique BST’s (binary search trees) that store values 1 … n. ExampleInput: 3 Output: 1234567[ [1,null,3, ...

Given n, how many structurally unique BST’s (binary search trees) that store values 1 … n? ExampleInput: 3 Output: 5 Explanation:Given n = 3, there ar ...

Given a non-negative index k where k ≤ 33, return the kth index row of the Pascal’s triangle. Note that the row index starts from 0. In Pascal’s tria ...