Start from integer 1, remove any integer that contains 9 such as 9, 19, 29... So now, you will have a new integer sequence: 1, 2, 3, 4, 5, 6, 7, 8, 10, 11, ... Given a positive integer n, you need to return the n-th integer after removing. Note that…

Given an array A (index starts at 1) consisting of N integers: A1, A2, ..., AN and an integer B. The integer B denotes that from any place (suppose the index is i) in the array A, you can jump to any one of the place in the array A indexed i+1, i+2,…

Given a sorted integer array nums, where the range of elements are in the inclusive range [lower, upper], return its missing ranges. example: Input: nums = [0, 1, 3, 50, 75], lower = 0 and upper = 99, Output: ["2", "4->49", "51…

A car travels from a starting position to a destination which is target miles east of the starting position. Along the way, there are gas stations.  Each station[i] represents a gas station that is station[i][0]miles east of the starting position, an…

Given a set of words (without duplicates), find all word squares you can build from them. A sequence of words forms a valid word square if the kth row and column read the exact same string, where 0 ≤ k < max(numRows, numColumns). For example, the wor…

We are given a list schedule of employees, which represents the working time for each employee. Each employee has a list of non-overlapping Intervals, and these intervals are in sorted order. Return the list of finite intervals representing common, p…

Given a list of words and two words word1 and word2, return the shortest distance between these two words in the list. word1 and word2 may be the same and they represent two individual words in the list. Example:Assume that words = ["practice",…

Design a class which receives a list of words in the constructor, and implements a method that takes two words word1 and word2 and return the shortest distance between these two words in the list. Your method will be called repeatedly many times with…

There is a ball in a maze with empty spaces and walls. The ball can go through empty spaces by rolling up(u), down (d), left (l) or right (r), but it won't stop rolling until hitting a wall. When the ball stops, it could choose the next direction. Th…

An image is represented by a binary matrix with 0 as a white pixel and 1 as a black pixel. The black pixels are connected, i.e., there is only one black region. Pixels are connected horizontally and vertically. Given the location (x, y) of one of the…