Hi all, I'm accustomed to teaching AQA D1 but am going to be teaching the Edexcel spec later this year so I need to make sure I'm not giving my students duff information on how to answer the questions to Edexcel's satisfaction. For anyone else who's in the same situation, so far I'm aware of the following differences: On AQA but not Edexcel: travelling salesman problem, pseudo English /pseudo-code, shuttle sort, Shell sort On Edexcel but not AQA: binary search (have yet to look up what this is!), bin packing algorithms, critical path analysis inc cascade & scheduling diagrams Differences between common topics: Quick sort: AQA use first number in list as pivot; Edexcel for some reason insist on using the middle one (or just after middle if an even number of items). Found a nice video by Mr Hegarty that demonstrates what Edexcel like to see. Matchings: AQA's alternating path algorithm = Edexcel's maximal matching algorithm. The Edexcel text book I've been given says you should write e.g. A - P = B - Q and then rewrite the same thing with the -s and =s swapped over, as well as listing the final matching. With AQA I just write A - P + B - Q (i.e. crossing out the link between B and P, not really a plus sign but that was the closest thing on the keyboard), then list the final matching. Would Edexcel be happy with that? Linear programming (no, autocorrect, not orgasming!): the text book mentions the possibility of having variables x, y and z but on a quick glance through the chapter I didn't see any examples with more than two variables. Do they come up? Sometimes on AQA you get three variables which are then reduced to two (e.g. the manufacturer makes the same number of Gold and Bronze packages) to allow a graph to be plotted. I've done most of the CPA stuff (except scheduling diagrams) in AQA Use of Maths but again, the presentation looks different, at least for the activity network: AQA have the activity on the node whereas Edexcel have it on the arc.