Thank you for the awnsers. I'm having some trouble understanding the codes tough.... In Roger's code what does the I. do? Here's how I read the code:
+/ I. ((-:|.)@#: *. (-:|.)@":)"0 i.1e6 from 1 to 1e6, check if the number is palyndrome in base 2 and in base 10. I. the bolean list // don't understand this part sum the elements In Mike's code, there's a nice speed boost, but I can't understand the code flow... How do you prevent from doing a test if the other test was false? I beleive it has to do with the * primitive... And if we wanted to do as Raul told and only test odd numbers, how do we go from 1 to 999999 jumping 2 numbers? That would cut the code execution time in half I beleive. ####################### I tried going back to problem 1 and adapting your solutions to it, but failed =( +/ 1e3 #~ ((3|"0)) +. (5|"0)) i. 1e3 NB. how do I access the current number from inside the ( ) ? Bruno ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
