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Archive for January 2020

Count Directories

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

Balls and Bins

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

Shortest Path in Directed Acyclic Graph

Problem Statement Given a weighted Directed Acyclic Graphs (DAG), find the shortest path to a particular point from the given starting point. One thing you can do is apply an O(N*N) algorithm and find the shortest distance by calculating all the distances from each node to every other node. As . . . Read more

Coin in Line

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

Replace And Remove

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

Out of Boundary Paths

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