Problem Statement Write a function to find the longest common prefix string amongst an array of strings. If there is no common prefix, return an empty string “”. Examples Solution

Problem Statement Given a directory change command cd a/b/../c/d/e/../../ output the visit count of each directory such as: {a=2, b=1, c=2, d=2, e=1}. Solution

Problem Statement Given m balls and n bin, find out how many ways exist to assign the balls to then bins. Note: the buckets have no order. That is, (1,2,3) and (3,2,1) are considered the same. Example Solution This can be solved using dynamic programming. The solution builds up upon . . . Read more

Problem Statement A and B are playing a game. At the beginning there are n coins. Given two more numbers x and y. In each move a player can pick x or y or 1 coins. A always starts the game. The player who picks the last coin wins the game. For . . . Read more

Problem Statement Consider the following two rules that are to be applied to strings over the alphabets: [‘a’, ‘b’, ‘c’, ‘d’] Replace each ‘a’ with ‘dd’ Delete each ‘b’ Solution

Problem Statement There is an m by n grid with a ball. Given the start coordinate (i,j) of the ball, you can move the ball to adjacent cell or cross the grid boundary in four directions (up, down, left, right). However, you can at most move N times. Find out . . . Read more

Problem Statement A robot is located at the top-left corner of a m x n grid (marked ‘Start’ in the diagram below). The robot can only move either down or right at any point in time. The robot is trying to reach the bottom-right corner of the grid (marked ‘Finish’ . . . Read more

Problem Statement We have two integer sequences A and B of the same non-zero length. We are allowed to swap elements A[i] and B[i]. Note that both elements are in the same index position in their respective sequences. At the end of some number of swaps, A and B are . . . Read more