Niv #19
Niv #19
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CheezItMan
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CheezItMan
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You hit most of the learning goals here. In particular you didn't use a circular buffer to implement a Queue. See my notes. Let me know if you want help with this.
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| def balanced(string) | ||
| raise NotImplementedError, "Not implemented yet" | ||
| pairs = {")" => "(", "}" => "{", "]"=>"["} |
lib/queue.rb
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| def enqueue(element) | ||
| raise NotImplementedError, "Not yet implemented" | ||
| @store.push(element) |
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This isn't using a circular buffer, it works, but not what I requested.
lib/queue.rb
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| def dequeue | ||
| raise NotImplementedError, "Not yet implemented" | ||
| removed = @store[0] | ||
| @store = @store[1..-1] |
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Just a note, dequeue is an O(n) operation because of how you're using the array here.
CheezItMan
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CheezItMan
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This is mostly good, a few bugs here and there. I've added some tests for next cohort to help catch them. Take a look at my comments and let me know if you have questions.
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| def enqueue(element) | ||
| raise NotImplementedError, "Not yet implemented" | ||
| if @front == 0 && @rear == @BUFFER_SIZE - 1 |
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This could run into trouble if the Queue becomes full and the front is not at index 0.
Consider if you had a buffer size of 10,
You add 9 elements, remove one (so front is at index 1) and then try to add 7 more. What happens?
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| def dequeue | ||
| raise NotImplementedError, "Not yet implemented" | ||
| removed_data = @store[@front] |
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Before dequeuing you should check to see if the queue is empty.
| if (@front == @rear) | ||
| @front = -1 | ||
| @rear = -1 | ||
| elsif @front === @BUFFER_SIZE - 1 |
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This kind of elsif statements work or you could do: @front = (@front + 1) % BUFFER_SIZE
| display_store = @store[@front...@rear+1] | ||
| else | ||
| first_half = @store[0...@rear] | ||
| second_half = @store[@front..@store.length+1] |
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Stacks and Queues
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Comprehension Questions
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