You might want to consider using a DiffArray, though if the backtracking is of just the wrong sort, you might get worse performance than you want. Updates are O(length xs) where xs is the list of updates to be performed (so O(1) in the singleton case), but lookups into older versions of the array get slower by a constant amount every time an update is performed. (The semantics are referentially transparent, the performance is not.) However, updating an old version will cause a fresh copy to be made, and lookups will be fast again after that.
On 03/12/06, Tony Morris <[EMAIL PROTECTED]> wrote:
I wish to pass a 2 dimensional array to use in a back-tracking algorithm. Since I will be doing lots of inserts, a Data.Array is unsuitable. It seems that a Map Int (Map Int a) is the most suitable structure, but this seems cumbersome. Is there anything more appropriate? -- Tony Morris http://tmorris.net/ _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
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