Permutations are for lists, order matters.Combinations are for groups, order does not matter. Better Explained Permutations A Permutation is an ordering of elements from a group of objects. Permutations of a set Say we have n elements and we want to arrange all of them with a specific order. To Read more…
Mergesort Mergesort is an efficient and widely used sorting algorithm. Stable sorting algorithm: preserves the order optimal time complexity: N log N in all cases suboptimal in space usage: usage of an extra array for merging Usage examples: Sorting Linked Lists when space is not a concern. Java default algorithm Read more…
This article contains a series of exercises on java arrays, including resizing array implementation, merging sorted arrays, etc.. Resizing-array implementation A Java ArrayList is a resizable-array implementation of the List interface providing amortized-time for insertion of O(1). Exercise: implement a ResizingArray class providing O(1) amortized-time for insertion. Growing the array Read more…
This article shows how to quickly build an EMF model using the Ecore Tools UML editor and generate the Java source code. For this article I am using eclipse eclipse-modeling-tools-2019-06. Modeling Motivations Main motivations for modeling and code generation: separation of application logic w.r.t. implementation: your independent model can be Read more…
In my development environment, I am running WordPress on docker containers, and I want a system to backup (and restore) both the DB and the WordPress data. For this article, I assume you are familiar with docker and Linux bash concepts. If you just want to backup a DB running Read more…
Sorting, searching, and binary search Divide-and-conquer Dynamic programming and memorization Greedy algorithms Recursion Graph traversal, BFS and DFS Sorting Main algorithms presented Mergesort: Java sort for Objects Quicksort: Java sort for primitive types Heapsort Mergesort vs Quicksort vs Heapsort All these algorithms have O(N log N) average time complexity, though Read more…
Good knowledge of common data structures is needed in computer science. This article describes common data structures, and present cost and benefits. Lists A List is an abstract data type representing a finite collection of ordered elements. Typically, a List is allocated dynamically depending on the implementation. For example, Array-based Read more…
You use maven in Eclipse, and need to work with multi-module (hierarchical) projects? This page shows how to create and work with maven multi-module projects in Eclipse. For this article, I am using eclipse-jee-2019-06, which already supports maven. If you use a different version of eclipse, make sure the m2e Read more…
Here are three examples covering maven basics in Eclipse such as: convert a java project to maven nature, create a project with an archetype selection, and refresh/update projects and understand files and structure. For the article, I use eclipse-jee-2019-06, which already provides maven support. If you use a different version Read more…
You need to import folders of your filesystem into Eclipse? Some possible motivations: You want to perform a full-text search on a directory in the filesystem You want to see the content of an existing project without importing it Assuming you have temp project, where you want to import the Read more…