add monotonic queue algorithm #10531
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require descriptive names
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| expect = [3, 3, 5, 5, 6, 7] | ||
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| def max_sliding_window(arr: list[float], k: int) -> list[float]: |
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Please provide descriptive name for the parameter: k
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I changed it to window_size
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| from __future__ import annotations | |||
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| from .double_ended_queue import Deque | |||
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Could this use https://docs.python.org/3/library/collections.html#collections.deque or is there a special capability in the local version?
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Yes we can. And so that we can avoid using private attributes
| queue = Deque() | ||
| for i in range(len(arr)): | ||
| # pop the element if the index is outside the window size k | ||
| if queue and i - queue._front.val >= window_size: |
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Using the private _front is fairly risky. I.e. Not future-proof.
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Yes! I use the collections.deque now
| expect = [3, 3, 5, 5, 6, 7] | ||
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| def max_sliding_window(arr: list[float], window_size: int) -> list[float]: |
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Can we take the same approach with this algorithm?
#10273 (comment)
Seems appropriate for a sliding_window algorithm.
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It is a bit different because the queue has to be monotonically decreasing while calculating the max value in a window.
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If it does not make sense then we can close the pull request.
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Hi, I resolved the issue of using collections.deque instead of double_ended_queue.
I feel the max sliding window is still an important algorithm which is a good use case of the queue (it is similar to next_greater_element in stack).
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@tianyizheng02 Is my iterator, not list request above unreasonable in this algorithm?
Describe your change:
Similar the monotonic stack implementation in next_greater_element.py, I implemented an epic monotonical queue example: max_sliding_window which is to continuously generate max value in a sliding window over an array.
I also implemented a test with one example and the test has passed.
Checklist: