So im trying to keep track of how many times each key on the keyboard is pressed, so I need something like a TreeMap that is ordered by variables. Anyone know a good data structure that takes care of this?
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What do you mean ordered? You need to specify what kind of order you're talking about here. – ColinD Nov 22 '10 at 01:22
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Lets say its a TreeMap
. It would be ordered from highest to lowest by the value, instead of the key. – Rahat Ahmed Nov 22 '10 at 16:54 -
Seems similar to [this](http://stackoverflow.com/questions/109383/how-to-sort-a-mapkey-value-on-the-values-in-java). – Dmitri Nov 22 '10 at 00:42
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Why not make an int array where key value corresponds to array index? As long as you aren't supporting beyond e.g. standard ASCII, this should be reasonable.
Armand
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That wouldn't be ordered. I'd probably make a method for that but i wanted to see if there was an easier way first – Rahat Ahmed Nov 22 '10 at 00:50
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Lets say its a TreeMap
. It would be ordered from highest to lowest by the value, instead of the key. – Rahat Ahmed Nov 22 '10 at 16:52 -
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Why not use a TreeMap? It has the ability to order its elements using a Comparator. You can define a class that implements Comparator which will determine which of two char's is "greater" than the other, thereby providing a means of ordering. I think String has a method for doing just this; your Comparator will just need to convert the char's into String's and then return the value of String.compare.
AniDev
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I tried this, but i get a NullPointerException when my TreeSet gets two objects to compare – Rahat Ahmed Nov 22 '10 at 03:55
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I figured out why, Java doesn't pass TreeMaps by reference so the map inside my comparator isn't the same as the one in my main code. – Rahat Ahmed Nov 22 '10 at 16:54