Re: [Haskell-cafe] Being impure within a 'pure' function

On Wed, Apr 22, 2009 at 10:38 AM, Daniel K. wrote:

Dijkstra's algorithm ... relies heavily on mutating arrays

Well, the imperative implementation does.

Not mutating the underlying arrays would probably result in poor performance.

Indeed. Non-mutable arrays are not very performant for mutations. Tree-like data structures Are Your Friend. I've never compared the performance of an ST-based implementation with a set/map based algorithm, but I've often found the latter usably performant. --Max