How to count the number of opened file descriptors of all running JVM's on a Linux host ?

for ((;;))
do
  declare sum=0
  for i in `pgrep -lf jdk | awk '{print $1}'`
  do
    ((sum += `sudo /usr/sbin/lsof -p $i | wc -l`))
  done
  echo "`date` java: $sum"
  sleep 5
done | tee fd-java.log

Or a faster alternative:

for ((;;))
do
  for i in `pgrep -lf jdk | awk '{print $1}'`
  do
    s="$s$i,"
  done
  echo "`date` java: `sudo /usr/sbin/lsof -p $s | wc -l`"
  sleep 5
done | tee fd-java.log

What if you need a break down per JVM ?

for ((;;))
do
  echo -n "`date` "
  for i in `pgrep -lf jdk | awk '{print $1}'`
  do
    echo -n "[$i]:"
    sudo /usr/sbin/lsof -p $i | wc -l | tr '\n' ','
    echo -n " "
  done
  echo ""
  sleep 5
done | tee fd-jvms.log

1. Download the bundle eg

   https://github.com/textmate/haskell.tmbundle/tarball/master

2. Uncompress the bundle eg

   tar xzf textmate-haskell.tmbundle-5d41f32.tgz

3. rename the directory to Haskell.tmbundle eg

   mv textmate-haskell.tmbundle-5d41f32 Haskell.tmbundle

4. mv Haskell.tmbundle /Library/Application\ Support/TextMate/Bundles/

5. Restart TextMate
   

  MATH
-   IS
------
   FUN

Given each alphabet is a digit, what are the possible solutions ?

(Don't scroll down if you want to give it a shot)





























Haskell in GHCI:

[(m,a,t,h,i,s,f,u,n)|m <- [0..9], a <- [0..9], t <- [0..9], h <- [0..9], i <- [0..9], s <- [0..9], f <- [0..9], u <- [0..9], n <- [0..9], (m*1000+a*100+t*10+h) - (i*10+s) == f*100+u*10+n, not (elem m [a,t,h,i,s,f,u,n]), not (elem a [t,h,i,s,f,u,n]), not (elem t [h,i,s,f,u,n]), not (elem h [i,s,f,u,n]), not (elem i [s,f,u,n]), not (elem s [f,u,n]), not (elem f [u,n]), not (u==n)]

Alternatively, a much faster version (in a main.hs for example):

module Main where
main :: IO ()
main = putStrLn (show 
    [(m,a,t,h,i,s,f,u,n)
    | m <- [0..9],
      a <- remove m [0..9],
      t <- remove' [m,a] [0..9],
      h <- remove' [m,a,t] [0..9],
      i <- remove' [m,a,t,h] [0..9],
      s <- remove' [m,a,t,h,i] [0..9],
      f <- remove' [m,a,t,h,i,s] [0..9],
      u <- remove' [m,a,t,h,i,s,f] [0..9],
      n <- remove' [m,a,t,h,i,s,f,u] [0..9],
      (m*1000+a*100+t*10+h) - (i*10+s) == f*100+u*10+n
    ])
    
-- remove an element once from the list
remove :: (Eq a) => a -> [a] -> [a]
remove _ [] = []
remove a (x:xs)
    | a == x = xs
    | otherwise = [x] ++ (remove a xs)
    
-- remove each element in the removal list once from the target list
remove' ::  (Eq a) => [a] -> [a] -> [a]
remove' _ [] = []
remove' [] xs = xs
remove' (a:as) bs = remove' as (remove a bs)

360 solutions:

M,A,T,H,I,S,F,U,N
0,2,3,4,5,6,1,7,8
0,2,3,4,5,8,1,7,6
0,2,3,4,7,6,1,5,8
0,2,3,4,7,8,1,5,6
0,2,3,5,4,6,1,8,9
0,2,3,5,4,9,1,8,6
0,2,3,5,8,6,1,4,9
0,2,3,5,8,9,1,4,6
0,2,3,6,4,7,1,8,9
0,2,3,6,4,9,1,8,7
0,2,3,6,8,7,1,4,9
0,2,3,6,8,9,1,4,7
0,2,3,9,6,4,1,7,5
0,2,3,9,6,5,1,7,4
0,2,3,9,7,4,1,6,5
0,2,3,9,7,5,1,6,4
0,2,4,3,5,6,1,8,7
0,2,4,3,5,7,1,8,6
0,2,4,3,6,5,1,7,8
0,2,4,3,6,8,1,7,5
0,2,4,3,7,5,1,6,8
0,2,4,3,7,8,1,6,5
0,2,4,3,8,6,1,5,7
0,2,4,3,8,7,1,5,6
0,2,4,6,5,7,1,8,9
0,2,4,6,5,9,1,8,7
0,2,4,6,8,7,1,5,9
0,2,4,6,8,9,1,5,7
0,2,5,3,6,4,1,8,9
0,2,5,3,6,9,1,8,4
0,2,5,3,8,4,1,6,9
0,2,5,3,8,9,1,6,4
0,2,5,7,6,3,1,9,4
0,2,5,7,6,4,1,9,3
0,2,5,7,9,3,1,6,4
0,2,5,7,9,4,1,6,3
0,2,5,9,7,3,1,8,6
0,2,5,9,7,6,1,8,3
0,2,5,9,8,3,1,7,6
0,2,5,9,8,6,1,7,3
0,2,6,3,7,4,1,8,9
0,2,6,3,7,9,1,8,4
0,2,6,3,8,4,1,7,9
0,2,6,3,8,9,1,7,4
0,2,6,4,7,5,1,8,9
0,2,6,4,7,9,1,8,5
0,2,6,4,8,5,1,7,9
0,2,6,4,8,9,1,7,5
0,2,6,8,7,3,1,9,5
0,2,6,8,7,5,1,9,3
0,2,6,8,9,3,1,7,5
0,2,6,8,9,5,1,7,3
0,3,1,5,4,7,2,6,8
0,3,1,5,4,8,2,6,7
0,3,1,5,6,7,2,4,8
0,3,1,5,6,8,2,4,7
0,3,1,7,4,8,2,6,9
0,3,1,7,4,9,2,6,8
0,3,1,7,6,8,2,4,9
0,3,1,7,6,9,2,4,8
0,3,4,6,5,7,2,8,9
0,3,4,6,5,9,2,8,7
0,3,4,6,8,7,2,5,9
0,3,4,6,8,9,2,5,7
0,3,4,7,5,1,2,9,6
0,3,4,7,5,6,2,9,1
0,3,4,7,9,1,2,5,6
0,3,4,7,9,6,2,5,1
0,3,4,8,5,1,2,9,7
0,3,4,8,5,7,2,9,1
0,3,4,8,9,1,2,5,7
0,3,4,8,9,7,2,5,1
0,3,5,1,6,4,2,8,7
0,3,5,1,6,7,2,8,4
0,3,5,1,8,4,2,6,7
0,3,5,1,8,7,2,6,4
0,3,5,8,6,1,2,9,7
0,3,5,8,6,7,2,9,1
0,3,5,8,9,1,2,6,7
0,3,5,8,9,7,2,6,1
0,3,6,4,7,5,2,8,9
0,3,6,4,7,9,2,8,5
0,3,6,4,8,5,2,7,9
0,3,6,4,8,9,2,7,5
0,3,6,5,7,1,2,9,4
0,3,6,5,7,4,2,9,1
0,3,6,5,9,1,2,7,4
0,3,6,5,9,4,2,7,1
0,3,7,5,8,1,2,9,4
0,3,7,5,8,4,2,9,1
0,3,7,5,9,1,2,8,4
0,3,7,5,9,4,2,8,1
0,3,7,6,8,1,2,9,5
0,3,7,6,8,5,2,9,1
0,3,7,6,9,1,2,8,5
0,3,7,6,9,5,2,8,1
0,4,1,5,2,6,3,8,9
0,4,1,5,2,9,3,8,6
0,4,1,5,8,6,3,2,9
0,4,1,5,8,9,3,2,6
0,4,1,6,2,7,3,8,9
0,4,1,6,2,9,3,8,7
0,4,1,6,8,7,3,2,9
0,4,1,6,8,9,3,2,7
0,4,1,9,5,2,3,6,7
0,4,1,9,5,7,3,6,2
0,4,1,9,6,2,3,5,7
0,4,1,9,6,7,3,5,2
0,4,2,7,5,8,3,6,9
0,4,2,7,5,9,3,6,8
0,4,2,7,6,8,3,5,9
0,4,2,7,6,9,3,5,8
0,4,2,9,5,1,3,7,8
0,4,2,9,5,8,3,7,1
0,4,2,9,7,1,3,5,8
0,4,2,9,7,8,3,5,1
0,4,5,1,6,2,3,8,9
0,4,5,1,6,9,3,8,2
0,4,5,1,8,2,3,6,9
0,4,5,1,8,9,3,6,2
0,4,5,8,6,1,3,9,7
0,4,5,8,6,7,3,9,1
0,4,5,8,9,1,3,6,7
0,4,5,8,9,7,3,6,1
0,4,6,1,7,2,3,8,9
0,4,6,1,7,9,3,8,2
0,4,6,1,8,2,3,7,9
0,4,6,1,8,9,3,7,2
0,4,7,6,8,1,3,9,5
0,4,7,6,8,5,3,9,1
0,4,7,6,9,1,3,8,5
0,4,7,6,9,5,3,8,1
0,5,1,3,2,6,4,8,7
0,5,1,3,2,7,4,8,6
0,5,1,3,8,6,4,2,7
0,5,1,3,8,7,4,2,6
0,5,1,6,2,7,4,8,9
0,5,1,6,2,9,4,8,7
0,5,1,6,8,7,4,2,9
0,5,1,6,8,9,4,2,7
0,5,1,9,3,2,4,8,7
0,5,1,9,3,7,4,8,2
0,5,1,9,8,2,4,3,7
0,5,1,9,8,7,4,3,2
0,5,2,6,3,7,4,8,9
0,5,2,6,3,9,4,8,7
0,5,2,6,8,7,4,3,9
0,5,2,6,8,9,4,3,7
0,5,2,7,3,1,4,9,6
0,5,2,7,3,6,4,9,1
0,5,2,7,9,1,4,3,6
0,5,2,7,9,6,4,3,1
0,5,2,8,3,1,4,9,7
0,5,2,8,3,7,4,9,1
0,5,2,8,9,1,4,3,7
0,5,2,8,9,7,4,3,1
0,5,3,9,6,1,4,7,8
0,5,3,9,6,8,4,7,1
0,5,3,9,7,1,4,6,8
0,5,3,9,7,8,4,6,1
0,5,6,1,7,2,4,8,9
0,5,6,1,7,9,4,8,2
0,5,6,1,8,2,4,7,9
0,5,6,1,8,9,4,7,2
0,5,6,2,7,3,4,8,9
0,5,6,2,7,9,4,8,3
0,5,6,2,8,3,4,7,9
0,5,6,2,8,9,4,7,3
0,5,6,3,7,1,4,9,2
0,5,6,3,7,2,4,9,1
0,5,6,3,9,1,4,7,2
0,5,6,3,9,2,4,7,1
0,5,7,3,8,1,4,9,2
0,5,7,3,8,2,4,9,1
0,5,7,3,9,1,4,8,2
0,5,7,3,9,2,4,8,1
0,6,1,2,3,4,5,7,8
0,6,1,2,3,8,5,7,4
0,6,1,2,7,4,5,3,8
0,6,1,2,7,8,5,3,4
0,6,1,3,2,4,5,8,9
0,6,1,3,2,9,5,8,4
0,6,1,3,8,4,5,2,9
0,6,1,3,8,9,5,2,4
0,6,1,7,2,3,5,9,4
0,6,1,7,2,4,5,9,3
0,6,1,7,9,3,5,2,4
0,6,1,7,9,4,5,2,3
0,6,1,9,3,2,5,8,7
0,6,1,9,3,7,5,8,2
0,6,1,9,8,2,5,3,7
0,6,1,9,8,7,5,3,2
0,6,2,1,3,4,5,8,7
0,6,2,1,3,7,5,8,4
0,6,2,1,4,3,5,7,8
0,6,2,1,4,8,5,7,3
0,6,2,1,7,3,5,4,8
0,6,2,1,7,8,5,4,3
0,6,2,1,8,4,5,3,7
0,6,2,1,8,7,5,3,4
0,6,2,8,3,1,5,9,7
0,6,2,8,3,7,5,9,1
0,6,2,8,9,1,5,3,7
0,6,2,8,9,7,5,3,1
0,6,3,1,4,2,5,8,9
0,6,3,1,4,9,5,8,2
0,6,3,1,8,2,5,4,9
0,6,3,1,8,9,5,4,2
0,6,3,8,4,1,5,9,7
0,6,3,8,4,7,5,9,1
0,6,3,8,9,1,5,4,7
0,6,3,8,9,7,5,4,1
0,6,7,3,8,1,5,9,2
0,6,7,3,8,2,5,9,1
0,6,7,3,9,1,5,8,2
0,6,7,3,9,2,5,8,1
0,6,7,4,8,1,5,9,3
0,6,7,4,8,3,5,9,1
0,6,7,4,9,1,5,8,3
0,6,7,4,9,3,5,8,1
0,7,1,3,2,4,6,8,9
0,7,1,3,2,9,6,8,4
0,7,1,3,8,4,6,2,9
0,7,1,3,8,9,6,2,4
0,7,1,4,2,5,6,8,9
0,7,1,4,2,9,6,8,5
0,7,1,4,8,5,6,2,9
0,7,1,4,8,9,6,2,5
0,7,1,8,2,3,6,9,5
0,7,1,8,2,5,6,9,3
0,7,1,8,9,3,6,2,5
0,7,1,8,9,5,6,2,3
0,7,1,9,3,4,6,8,5
0,7,1,9,3,5,6,8,4
0,7,1,9,8,4,6,3,5
0,7,1,9,8,5,6,3,4
0,7,2,4,3,5,6,8,9
0,7,2,4,3,9,6,8,5
0,7,2,4,8,5,6,3,9
0,7,2,4,8,9,6,3,5
0,7,2,5,3,1,6,9,4
0,7,2,5,3,4,6,9,1
0,7,2,5,9,1,6,3,4
0,7,2,5,9,4,6,3,1
0,7,3,1,4,2,6,8,9
0,7,3,1,4,9,6,8,2
0,7,3,1,8,2,6,4,9
0,7,3,1,8,9,6,4,2
0,7,4,1,5,2,6,8,9
0,7,4,1,5,9,6,8,2
0,7,4,1,8,2,6,5,9
0,7,4,1,8,9,6,5,2
0,7,4,2,5,3,6,8,9
0,7,4,2,5,9,6,8,3
0,7,4,2,8,3,6,5,9
0,7,4,2,8,9,6,5,3
0,7,4,3,5,1,6,9,2
0,7,4,3,5,2,6,9,1
0,7,4,3,9,1,6,5,2
0,7,4,3,9,2,6,5,1
0,8,1,2,4,3,7,6,9
0,8,1,2,4,9,7,6,3
0,8,1,2,6,3,7,4,9
0,8,1,2,6,9,7,4,3
0,8,2,3,5,4,7,6,9
0,8,2,3,5,9,7,6,4
0,8,2,3,6,4,7,5,9
0,8,2,3,6,9,7,5,4
0,8,2,5,3,1,7,9,4
0,8,2,5,3,4,7,9,1
0,8,2,5,9,1,7,3,4
0,8,2,5,9,4,7,3,1
0,8,2,6,3,1,7,9,5
0,8,2,6,3,5,7,9,1
0,8,2,6,9,1,7,3,5
0,8,2,6,9,5,7,3,1
0,8,3,6,4,1,7,9,5
0,8,3,6,4,5,7,9,1
0,8,3,6,9,1,7,4,5
0,8,3,6,9,5,7,4,1
0,8,4,3,5,1,7,9,2
0,8,4,3,5,2,7,9,1
0,8,4,3,9,1,7,5,2
0,8,4,3,9,2,7,5,1
0,8,5,3,6,1,7,9,2
0,8,5,3,6,2,7,9,1
0,8,5,3,9,1,7,6,2
0,8,5,3,9,2,7,6,1
0,8,5,4,6,1,7,9,3
0,8,5,4,6,3,7,9,1
0,8,5,4,9,1,7,6,3
0,8,5,4,9,3,7,6,1
0,9,1,2,4,5,8,6,7
0,9,1,2,4,7,8,6,5
0,9,1,2,6,5,8,4,7
0,9,1,2,6,7,8,4,5
0,9,1,5,4,2,8,7,3
0,9,1,5,4,3,8,7,2
0,9,1,5,7,2,8,4,3
0,9,1,5,7,3,8,4,2
0,9,1,7,5,3,8,6,4
0,9,1,7,5,4,8,6,3
0,9,1,7,6,3,8,5,4
0,9,1,7,6,4,8,5,3
0,9,2,1,4,5,8,7,6
0,9,2,1,4,6,8,7,5
0,9,2,1,5,4,8,6,7
0,9,2,1,5,7,8,6,4
0,9,2,1,6,4,8,5,7
0,9,2,1,6,7,8,5,4
0,9,2,1,7,5,8,4,6
0,9,2,1,7,6,8,4,5
0,9,2,4,5,1,8,7,3
0,9,2,4,5,3,8,7,1
0,9,2,4,7,1,8,5,3
0,9,2,4,7,3,8,5,1
0,9,3,5,6,1,8,7,4
0,9,3,5,6,4,8,7,1
0,9,3,5,7,1,8,6,4
0,9,3,5,7,4,8,6,1
1,0,2,3,4,5,9,7,8
1,0,2,3,4,8,9,7,5
1,0,2,3,7,5,9,4,8
1,0,2,3,7,8,9,4,5
1,0,3,2,4,5,9,8,7
1,0,3,2,4,7,9,8,5
1,0,3,2,5,4,9,7,8
1,0,3,2,5,8,9,7,4
1,0,3,2,7,4,9,5,8
1,0,3,2,7,8,9,5,4
1,0,3,2,8,5,9,4,7
1,0,3,2,8,7,9,4,5
1,0,3,4,5,6,9,7,8
1,0,3,4,5,8,9,7,6
1,0,3,4,7,6,9,5,8
1,0,3,4,7,8,9,5,6
1,0,3,6,5,2,9,8,4
1,0,3,6,5,4,9,8,2
1,0,3,6,8,2,9,5,4
1,0,3,6,8,4,9,5,2
1,0,4,3,5,6,9,8,7
1,0,4,3,5,7,9,8,6
1,0,4,3,6,5,9,7,8
1,0,4,3,6,8,9,7,5
1,0,4,3,7,5,9,6,8
1,0,4,3,7,8,9,6,5
1,0,4,3,8,6,9,5,7
1,0,4,3,8,7,9,5,6
1,0,4,5,6,2,9,8,3
1,0,4,5,6,3,9,8,2
1,0,4,5,8,2,9,6,3
1,0,4,5,8,3,9,6,2
1,0,4,7,6,2,9,8,5
1,0,4,7,6,5,9,8,2
1,0,4,7,8,2,9,6,5
1,0,4,7,8,5,9,6,2
1,0,5,6,7,2,9,8,4
1,0,5,6,7,4,9,8,2
1,0,5,6,8,2,9,7,4
1,0,5,6,8,4,9,7,2

... in response to another 6th grader's home work assignment :)

  TAKE
+ HOME
------
  EXAM

Given each alphabet is a digit, what are the possible solutions ?

(Don't scroll down if you want to give it a shot)





























Haskell in GHCI:

[(t,a,k,e,h,o,m,x)|t <- [0..9], a <- [0..9], k <- [0..9], e <- [0..9], h <- [0..9], o <- [0..9], m <- [0..9], x <- [0..9], (t*1000+a*100+k*10+e) + (h*1000+o*100+m*10+e) == e*1000+x*100+a*10+m, not (elem t [a,k,e,h,o,m,x]), not (elem a [k,e,h,o,m,x]), not (elem k [e,h,o,m,x]), not (elem e [h,o,m,x]), not (elem h [o,m,x]), not (elem o [m,x]), not (m==x)]

Alternatively, a much faster version (in a main.hs for example):

module Main where
main :: IO ()
main = putStrLn (show 
    [ (t,a,k,e,h,o,m,x)
    | t <- [0..9],
      a <- remove t [0..9],
      k <- remove' [t,a] [0..9],
      e <- remove' [t,a,k] [0..9],
      h <- remove' [t,a,k,e] [0..9],
      o <- remove' [t,a,k,e,h] [0..9],
      m <- remove' [t,a,k,e,h,o] [0..9],
      x <- remove' [t,a,k,e,h,o,m] [0..9],
      (t*1000+a*100+k*10+e) + (h*1000+o*100+m*10+e) == e*1000+x*100+a*10+m
    ])
    
-- remove an element once from the list
remove :: (Eq a) => a -> [a] -> [a]
remove _ [] = []
remove a (x:xs)
    | a == x = xs
    | otherwise = [x] ++ (remove a xs)
    
-- remove each element in the removal list once from the target list
remove' ::  (Eq a) => [a] -> [a] -> [a]
remove' _ [] = []
remove' [] xs = xs
remove' (a:as) bs = remove' as (remove a bs)

124 possible solutions:

T,A,K,E,H,O,M,X
0,4,1,6,5,9,2,3
0,5,7,4,3,6,8,2
0,5,9,3,2,8,6,4
0,7,1,3,2,8,6,5
0,7,3,2,1,8,4,5
0,7,3,2,1,9,4,6
0,9,1,4,3,6,8,5
0,9,1,4,3,7,8,6
0,9,2,8,7,4,6,3
0,9,2,8,7,5,6,4
0,9,5,2,1,7,4,6
0,9,5,2,1,8,4,7
1,0,2,4,3,5,8,6
1,0,2,4,3,6,8,7
1,0,3,8,7,4,6,5
1,0,4,3,2,7,6,8
1,0,4,3,2,8,6,9
1,0,5,7,6,2,4,3
1,0,5,7,6,8,4,9
1,0,7,6,5,3,2,4
1,0,7,6,5,8,2,9
1,2,5,8,7,0,6,3
1,3,0,6,5,4,2,7
1,3,2,5,4,6,0,9
1,3,4,9,7,6,8,0
1,3,5,4,2,6,8,0
1,3,8,7,5,6,4,0
1,3,8,7,6,5,4,9
1,4,8,3,2,0,6,5
1,5,0,7,6,3,4,8
1,5,6,9,7,4,8,0
1,5,7,4,3,0,8,6
1,7,3,2,0,8,4,5
1,7,3,2,0,9,4,6
1,7,6,5,4,2,0,9
1,7,9,4,2,5,8,3
1,8,3,7,5,2,4,0
1,8,5,6,4,9,2,7
1,8,7,5,3,4,0,2
1,8,7,5,3,6,0,4
1,9,5,2,0,7,4,6
1,9,5,2,0,8,4,7
1,9,8,5,3,7,0,6
2,0,1,9,7,3,8,4
2,0,1,9,7,4,8,5
2,0,1,9,7,5,8,6
2,0,4,3,1,7,6,8
2,0,4,3,1,8,6,9
2,3,4,9,6,7,8,1
2,3,4,9,7,1,8,5
2,3,5,4,1,6,8,0
2,4,5,9,7,1,8,6
2,4,8,3,1,0,6,5
2,5,9,3,0,8,6,4
2,6,1,7,5,3,4,9
2,7,0,8,5,4,6,1
2,7,1,3,0,8,6,5
2,7,6,5,3,1,0,8
2,7,9,4,1,5,8,3
2,8,3,7,5,1,4,9
2,8,7,5,3,1,0,9
3,0,1,9,6,4,8,5
3,0,2,4,1,5,8,6
3,0,2,4,1,6,8,7
3,1,2,9,6,5,8,7
3,1,4,8,5,0,6,2
3,1,4,8,5,7,6,9
3,2,5,8,4,7,6,0
3,4,5,9,6,2,8,7
3,5,7,4,0,6,8,2
3,5,7,4,1,0,8,6
3,6,7,9,5,4,8,1
3,7,0,8,4,5,6,2
3,7,0,8,5,2,6,9
3,7,6,5,2,1,0,8
3,8,7,5,1,4,0,2
3,8,7,5,1,6,0,4
3,8,7,5,2,1,0,9
3,9,1,4,0,6,8,5
3,9,1,4,0,7,8,6
3,9,2,8,4,1,6,0
3,9,8,5,1,7,0,6
4,0,1,9,5,2,8,3
4,0,1,9,5,6,8,7
4,2,5,8,3,7,6,0
4,3,2,5,1,6,0,9
4,7,0,8,3,5,6,2
4,7,6,5,1,2,0,9
4,8,5,6,1,9,2,7
4,9,2,8,3,1,6,0
5,0,1,9,4,2,8,3
5,0,1,9,4,6,8,7
5,0,7,6,1,3,2,4
5,0,7,6,1,8,2,9
5,1,4,8,3,0,6,2
5,1,4,8,3,7,6,9
5,3,0,6,1,4,2,7
5,3,8,7,1,6,4,0
5,4,1,6,0,9,2,3
5,6,1,7,2,3,4,9
5,6,7,9,3,4,8,1
5,7,0,8,2,4,6,1
5,7,0,8,3,2,6,9
5,8,3,7,1,2,4,0
5,8,3,7,2,1,4,9
6,0,1,9,3,4,8,5
6,0,5,7,1,2,4,3
6,0,5,7,1,8,4,9
6,1,2,9,3,5,8,7
6,3,4,9,2,7,8,1
6,3,8,7,1,5,4,9
6,4,5,9,3,2,8,7
6,5,0,7,1,3,4,8
7,0,1,9,2,3,8,4
7,0,1,9,2,4,8,5
7,0,1,9,2,5,8,6
7,0,3,8,1,4,6,5
7,2,5,8,1,0,6,3
7,3,4,9,1,6,8,0
7,3,4,9,2,1,8,5
7,4,5,9,2,1,8,6
7,5,6,9,1,4,8,0
7,9,2,8,0,4,6,3
7,9,2,8,0,5,6,4

... in response to a 6th grader's home work assignment :)

To use Haskell to find a right angle triangle that has:

• all three sides as integers
  
• each side less than or equal to 10
  
• a perimeter of 24
  

In ghci, type:

[(a,b,c) | c <- [1..10], b <- [1..c], a <- [1..b], a+b+c == 24, a^2+b^2 == c^2]

Output:

[(6,8,10)]

Pretty amazing :)