sorry- I originally used + which duplicated 15 where I should have
used or (+. )
On 08/04/2014 8:52 PM, Don Kelly wrote:
try=: 3 : '( (0=3|y)+.(0=5|y))#y' **or** try1=: ] #~ (0 = 3 | ]) +. 0
= 5 | ] *
*
try1 1+i.19
3 5 6 9 10 12 15 18
Don Kelly
On 08/04/2014 8:30 AM, Jon Hough wrote:
Euler Project #1 is:If we list all the natural numbers below 10 that
are multiples of 3 or 5, we get 3, 5, 6 and 9. The sum of these
multiples is 23. Find the sum of all the multiples of 3 or 5 below 1000.
In C/Java I could easily do something like:
int total =0;
for (int counter = 0; counter < 1000; counter ++ ){if(counter %3 = 0
|| counter %5 = 0){ total += counter;}}
return counter;
The main features here being the if statement and the for-loop.
Obviously in J things need to be done differently. Here is my first
attempt:
div3 =. 0&(="0)@:( 3&|) NB. is residue zerodiv5 =. 0&(="0)@:( 5&|)
div3or5 =. div3"0 +."0 div5"0
dummy =. 1&*"0 NB. You'll see why I need this...
result =. dummy * div3or5
NB. final result is:
+/result i.1000
I used dummy because I wanted to do something like multiply the
value of y by "div3or5 y" so only multiples of 3 or 5 would be nonzero.
Before attempting this problem I assumed it could be done in only one
line and am pretty unhappy by my long solution. Any help explaining
where I have gone wrong, or why my attempt at a fork is silly would
be appreciated.
Thanks in advance,
Jon
----------------------------------------------------------------------
For information about J forums see http://www.jsoftware.com/forums.htm
----------------------------------------------------------------------
For information about J forums see http://www.jsoftware.com/forums.htm
----------------------------------------------------------------------
For information about J forums see http://www.jsoftware.com/forums.htm
