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    <p>There are probably many ways that you could go about this. Most of which are not known to me. However I have recently solved a similar problem in two different ways:</p> <h1>Two Dimensional Array</h1> <p>Implementing the "Map" as a two Dimensional Array is the obvious solution. Most likely for this scenario you will want an <code>List</code> implementation so that you can resize easily. It will however require nested loops and such to search for a particular location, and the indexes might become somewhat confusing.</p> <h1>Map</h1> <p>A (in my opinion) better way to solve this problem would be to use a <code>Map</code>. You should create a <code>Position</code> class that has two variables (or three for a three-dimensional map) that record the X and Y position (Make sure you also implement the <code>equals()</code> and <code>hashCode()</code> methods). You can then use a <code>Position</code> object as the key in a <code>Map</code> implementation, stored against instances of <code>Animal</code>. This will allow for faster searching of a particular location (see <a href="https://stackoverflow.com/questions/1518103/hashmap-vs-arraylist-performance-am-i-correct">HashMap vs ArrayList performance am I correct</a>), and tidier code, ie no nested loops when iterating over the whole map. You can loop over the whole map like this:</p> <pre><code>for(Map.Entry&lt;Position, Animal&gt; entry : animalMap.getEntries()){ //Do stuff } </code></pre> <p>A couple of years ago I saw a tutorial project that implemented a Fox/Rabbit simulation. You may want to have a look at that for some ideas: <a href="http://www.bluej.org/objects-first/" rel="nofollow noreferrer">http://www.bluej.org/objects-first/</a></p> <p>You need to download the "Book Projects" .zip file. The relevant project is in Chapter 10.</p>
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    1. CONot sure where you get that a Map would be faster than an array, or how you would remove nested loops. With an array it is [x][y] - no searching at all, direct access. If you want to go through app Positions in the Map you are still going to have nested loops to build all the Positions.
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    2. CO@TofuBeer I am assuming that the OP would require a re-sizable array (ArrayList for instance). In this case access performance would be better with a Map implementation. No nested loops are required to go through the entire map.
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    3. COI wouldn't assume an ArrayList, the poster said 2d array. An ArrayList of ArrayLists would still be faster than a Map. Either way I don't think speed should be a factor, none of them are going to be especially slow. If you want to go through the Map, Position by Position for a range (say 1,2 to 5,7) you are going to need a nested loop. If you have another way to do it I'd love to hear it.
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