[['kitten', 2], ['dog', 2], ['rabbit', 2]]
Here the second value (an integer) represents item priority. If we enqueue ['human', 1]
with a priority of 1
(assuming lower priorities are given precedence) it would then be the first item to be dequeued. The collection would look like this:
[['human', 1], ['kitten', 2], ['dog', 2], ['rabbit', 2]]
.
We’ve started writing a PriorityQueue
in the code editor. You will need to add an enqueue
method for adding items with a priority, a dequeue
method for removing and returning items, a size
method to return the number of items in the queue, a front
method to return the element at the front of the queue, and finally an isEmpty
method that will return true
if the queue is empty or false
if it is not.
The enqueue
should accept items with the format shown above (['human', 1]
) where 1
represents the priority. dequeue
and front
should return only the item's name, not its priority.
PriorityQueue
class should have a enqueue
method.
testString: assert((function(){var test = new PriorityQueue(); return (typeof test.enqueue === 'function')}()));
- text: Your PriorityQueue
class should have a dequeue
method.
testString: assert((function(){var test = new PriorityQueue(); return (typeof test.dequeue === 'function')}()));
- text: Your PriorityQueue
class should have a size
method.
testString: assert((function(){var test = new PriorityQueue(); return (typeof test.size === 'function')}()));
- text: Your PriorityQueue
class should have a front
method.
testString: assert((function(){var test = new PriorityQueue(); return (typeof test.front === 'function')}()));
- text: Your PriorityQueue
class should have an isEmpty
method.
testString: assert((function(){var test = new PriorityQueue(); return (typeof test.isEmpty === 'function')}()));
- text: Your PriorityQueue
class should correctly keep track of the current number of items using the size
method as items are enqueued and dequeued.
testString: assert((function(){var test = new PriorityQueue(); test.enqueue(['David Brown', 2]); test.enqueue(['Jon Snow', 1]); var size1 = test.size(); test.dequeue(); var size2 = test.size(); test.enqueue(['A', 3]); test.enqueue(['B', 3]); test.enqueue(['C', 3]); return (size1 === 2 && size2 === 1 && test.size() === 4)}()));
- text: The front
method should return the correct item at the front of the queue as items are enqueued and dequeued.
testString: assert((function(){var test = new PriorityQueue(); test.enqueue(["David Brown", 2]); var front1 = test.front(); test.enqueue(["Jon Snow", 1]); var front2 = test.front(); test.dequeue(); test.enqueue(["A", 3]); var front3 = test.front(); test.enqueue(["B", 3]); test.enqueue(["C", 3]); test.dequeue(); var front4 = test.front(); return (front1 === "David Brown" && front2 === "Jon Snow" && front3 === "David Brown" && front4 === "A");})());
- text: The isEmpty
method should return true
when the queue is empty.
testString: assert((function(){var test = new PriorityQueue(); test.enqueue(['A', 1]); test.enqueue(['B', 1]); test.dequeue(); var first = test.isEmpty(); test.dequeue(); return (!first && test.isEmpty()); }()));
- text: The priority queue should return items with a higher priority before items with a lower priority and return items in first-in-first-out order otherwise.
testString: assert((function(){var test = new PriorityQueue(); test.enqueue(['A', 5]); test.enqueue(['B', 5]); test.enqueue(['C', 5]); test.enqueue(['D', 3]); test.enqueue(['E', 1]); test.enqueue(['F', 7]); var result = []; result.push(test.dequeue()); result.push(test.dequeue()); result.push(test.dequeue()); result.push(test.dequeue()); result.push(test.dequeue()); result.push(test.dequeue()); return result.join('') === 'EDABCF';}()));
```