Make Your Dijkstra Faster

Today I stumbled over yet another minor trick which could speed up the execution of the Dijkstra algorithm. Let me shortly introduce this shortest path algorithm: If you need the path (and not only the shortest path tree) you will give the method an additional toNode parameter and compare this to distEntry.node to break the … Continue reading »

Spatial Keys – Memory Efficient Geohashes

When you are operating on geographical data you’ll use latitude and longitude to specify a location somewhere on earth. To look up some associated information or if you want to do neighborhood searches you could create R-trees, quad-trees or similar spatial data structures to make them efficient. Some people are using Geohashes instead because then … Continue reading »

Free Online Graph Theory Books and Resources

A link compilation of some Hackernews and Stackoverflow posts and a longish personal investigation. The DaMN book and its companion book Graph Theory with Applications, J.A. Bondy and U.S.R. Murty Graph Theory, Reinhard Diestel Graph Theory Tutorials Digraphs: Theory, Algorithms and Applications, 1st Edition Wikipedia – Graph Algorithms Algorithms and Complexity, Herbert S. Wilf Lecture … Continue reading »

Rage Against the Android #eclipse

Developing Android applications on Linux with Eclipse sometimes can get really ugly. Sadly neither NetBeans which has a really nice Android plugin, but cannot execute a single test nor IDEA can rescue me or make me switching but probably they wouldn’t rescue me due to problems of Android development kit itself – I’m not sure. … Continue reading »