geekitarian

Think about this MaxHeap: 0 1 2 3 4 5 6 23 12 19 7 10 18 14 Remember, children are found with this formula: Left child: 2i + 1 Right child: 2i + 2 Parents are found with this formula: Parent: (i - 1) / 2 If we have a maxheap, the children are smaller than the parents.  If we have a minheap, the children are larger than the parents.  This is a maxheap, so all parents are larger than their children. To add to a maxheap, we put the new value at the next available position in the array then swap up.  In the file for your assignment, we call this process reheapUp. If we add the value 20 to the maxheap above, we get this: 0 1 2 3 4 5 6 7 23 12 19 7 10 18 14 20 We swap 20 (index 7) with its parent, if the parent is smaller.  The parent value is 7 (index 3) so we swap up. 0 1 2 3 4 5 6 7 23 12 19 20 10 18 14 7 We swap 20 (index 3) ...

Let’s say we already have a binary tree, and we want to build an Iterator to return the nodes in our tree in order.  If we were just listing the nodes, we could follow this recursive algorithm: Go to the left child (if it exists) Output the current node Go to the right child (if it exists) Consider this tree: We would start at the root (M); we’d immediately go to the left (F), then go to the left again (A).  There are no more values to go to the left, so we’d output the current node (A).  Then we’d go to the right - but there’s nothing to the right of A.  So we’d return.  This would return us to the previous level of recursion, where we’d output the current node (F).  We’d then go to the right (K); the next step would be to go to the left (J), then go to the left again (G).  We’d then output G as there’s no further left to go to; there’s nothing to the right, so we’d return to previous level of recursion (J).  We’d output J, an...

Coding with Chrome is a new Google application that's built to help people learn how to code.  It supports Blockly, CoffeeScript, Pencil Code, and JavaScript.  It's free to download and works right your the Chrome browser. I've been working on some educational material for the new application.  One of the things I really like about it is that it provides a really simple drawing API so you can easily code shapes and drawings instead of starting off with the command line.  Since the application gives you an immediate response, you're able to experiment and see how changing your code affects the picture on the screen. Here's what I've learned about the basic drawing API.  You can download this file and try experimenting with the code yourself. /*  * draw.clear() clears the screen.  */ draw.clear(); /*  * draw.point(x, y, color, size) draws the specified point on the screen in the  * specified color.  *  * @param {numb...