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queues/README.md

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 ## queues 
 
+<br>
+
+* first in, first out structures (FIFO), i.e., items are removed at the same order they are added.
+* queues can be implemented with two arrays or a dynamic array (linked list), as long as items are added and removed from opposite sides.
+* if implemented with a dynamic array, a more efficient solution is to use a circular queue (ring buffer), i.e. a fixed-size array and two pointers to indicate the starting and ending positions. an advantage of circular queues is that we can use the spaces in front of the queue. in a normal queue, once the queue becomes full, we cannot insert the next element even if there is a space in front of the queue. but using the circular queue, we can use the space to store new values.
+* queues are often used in breath-first search (where you store a list of nodes to be processed) or when implementing a cache.
+
+
+<br>
+
+----
+
+### examples
+
+<br>
+
+#### `queues.py`
+
+<br>
+
+```python
+> python3 queues.py
+
+🧪 Testing Queue...
+Is the queue empty? True
+Adding 1 to 10 in the queue...
+Queue: [10, 9, 8, 7, 6, 5, 4, 3, 2, 1]
+
+Queue size: 10
+Queue peek : 1
+Is the queue empty? False
+
+Dequeue...
+Queue: [10, 9, 8, 7, 6, 5, 4, 3, 2]
+
+Queue size: 9
+Queue peek: 2
+Is the queue empty? False
+
+
+🧪 Testing Priority Queue...
+Priority Queue: [(-4, 1, Item 4), (-1, 0, Item 1), (-3, 2, Item 3)]
+Pop: Item 4
+Priority Queue: [(-3, 2, Item 3), (-1, 0, Item 1)]
+```
+
+<br>