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The behavior function is an idea that spawned during the last few days when I thought about how I would program an industrial robot (the ‘classic’ orange robot). Using behavior functions, robots can be programmed in a more functional way. … Continue reading
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Algorithm examples in clojure
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The wikipedia page algorithm contains two simple examples of algorithms. Even though they are simple, the code examples really aren’t that beautiful. The first example is: find the largest number in a list.
=> (reduce (fn [x y] (if (> y x) y x)) [3 1 6 3 5 2]) 6
The second example is calculating the largest common divisor with euclid’s algorithm. There is an “elegant” code example as follows:
5 REM Euclid's algorithm for greatest common divisor 6 PRINT "Type two integers greater than 0" 10 INPUT A,B 20 IF B=0 THEN GOTO 80 30 IF A > B THEN GOTO 60 40 LET B=B-A 50 GOTO 20 60 LET A=A-B 70 GOTO 20 80 PRINT A 90 END
Well… it is simple, and it is probably fast as well, but elegant?
=> (loop [a 3009 b 884] (if (zero? b) a (recur b (rem a b)))) 17 => (loop [a 40902 b 24140] (if (zero? b) a (recur b (rem a b)))) 34
Success!!
Not only is this a lot more elegant (in my opinion), it also works when a = 0, where the “elegant” algorithm fails to end.
