Re: [Haskell-cafe] Solving a geometry problem with Haskell

12 Jan 2008


      On Jan 12, 2008 9:19 PM, Rafael Almeida  wrote:
...
After some profiling I found out that about 94% of the execution time is
spent in the ``isPerfectSquare'' function.
That function is quite inefficient for large numbers.  You might try
something like this:

isPerfectSquare n = searchSquare 0 n
    where
    searchSquare lo hi
      | lo == hi = False
      | otherwise =
          let mid = (lo + hi) `div` 2 in
          case mid^2 `compare` n of
              EQ -> True
              LT -> searchSquare mid hi
              GT -> searchSquare lo mid

Luke

Re: [Haskell-cafe] Solving a geometry problem with Haskell

Luke Palmer