Dijkstra's algorithm is completely trivial. It's a greedy algorithm; there's nothing more complex involved than repeating the same simple step over and over. You pick a starting node then repeatedly add the lowest-cost edge to a node you haven't already reached. It's harder to explain what a "node" and "edge" are than to explain how Dijkstra's algorithm works.

Many textbooks make it sound harder than that because they want to examine complex data structures that make various parts of that as fast as possible. But the complexity is the implementation of the data structures, not Dijkstra's algorithm.

indeed. and I can confirm I learned this algorithm back in the day in 8th grade, as we were given home assignments and myself had to read through a book 'introduction to Graphs' which was designated for 2nd university year students.

I was able to read halfway through the book before it started getting too complex for my teen mind.

so, can it be taught? - yes is it trivial - I would not dare say, but is elegant in simplicity do people understand and remember it easily - no, they don't

should you decide to prove me right, well - try to teach it to someone, but also require that he not only understands but implements it. well those who could do this in 8th grade were those going to Olympiads in Informatics.

perhaps things have changed since the 90s and children are smarter today. so my bet is you can teach it to 5th graders, not sure to what effect though.

Dijkstra _could_ be universally taught in 7th grade if we had the curriculum for that. Maybe I'm biased, but it doesn't seem conceptually significantly more difficult than solving first degree equations, and we teach those in 7th grade, at least in Finland where I'm from.

Depends on which school, as this is not taught at all outside mathematics school. My claim is you can teach it to 5th graders, this is what I tell my university students and I mean it.

Myself and others from the math schools knew this algorithm in 8th grade for sure, as we been already using it in 9th grade for competitions. This does not mean all my classmates knew it, of course not.

So it depends who you teach this to. Theoretically - you should be able to, practically - well, perhaps not so much, as math is not the only thing 8th grader learns, in fact his head is bombarded with ... dozen disciplines at a time.

Besides, I recently met a classmate, previous IoI medalist, who works quant-something somewhere for 15th + years, and is a PHD and everything. We start talking about mathematics and I find to my total surprise he knows very little about grammars, never used them. He remembers Dijkstra or Ford-Fulkerson, but only as a title, while I'm sure he learned these at some point in Stanford, as the shortest-path and A* was not something we had in textbooks back in the 90s for sure.

For sure! The main thing keeping us from teaching advanced things to younger folks is the seeming addiction to teaching poorly/ineffectively. I'm here to find the physical play-with-your-hands demonstrations needed for teaching kids as young as 5 the intuitions/concepts behind higher-order category theory without all the jargon.

I think you could do it with many board games. Mouse Trap for monads? Poker for permutations? Dice for decision theory?

I think we forget how old the term algorithm is. We started this journey trying to automate human tasks by divide and conquer, not computers.

Merge sort is supposedly invented in 1950, it’s more likely it was invented in 1050 than 1950. Sort a room full of documents for me. You have three minions, go.

> I think we forget how old the term algorithm is.

given Al Kwarizimi lived ~12 century (if memory serves right) it is a fairly old term in this regard.

when was it that modern people started using the word, I'd bet beginning of 20th century, but this is a wild guess.

when did everyone started calling algorithms "ai", well perhaps ~1960 ?

I think humans generally use some form of bucket/radix sorting (or selection sort for small collections)

A human is different than “humans” a human with a stack may sort it into four stacks and then sort amongst them, yes.

But a room of five clerks all taking tasks off a pile and then sorting their own piles is merge sort at the end of the day. Literally, and figuratively.