list | C doubly linked list

From the cpython source code for sum sum initially seems to attempt a fast path that assumes all inputs are the same type. If that fails it will just iterate:

It looks like a temporary issue, the server with these libraries is down. I have the same problem now with Room:

Return only len(a) elements from zip_longest:

This problem has a fun O(n) solution.

If you draw a graph of cumulative sum vs index, then:

The average value in the subarray between any two indexes is the slope of the line between those points on the graph.

The first highest-average-prefix will end at the point that makes the highest angle from 0. The next highest-average-prefix must then have a smaller average, and it will end at the point that makes the highest angle from the first ending. Continuing to the end of the array, we find that...

These segments of highest average are exactly the segments in the upper convex hull of the cumulative sum graph.

Find these segments using the monotone chain algorithm. Since the points are already sorted, it takes O(n) time.

Terraform AWS Provider is upgraded to version 4.0.0 which is published on 10 February 2022.

Major changes in the release include:

• Version 4.0.0 of the AWS Provider introduces significant changes to the aws_s3_bucket resource.
• Version 4.0.0 of the AWS Provider will be the last major version to support EC2-Classic resources as AWS plans to fully retire EC2-Classic Networking. See the AWS News Blog for additional details.
• Version 4.0.0 and 4.x.x versions of the AWS Provider will be the last versions compatible with Terraform 0.12-0.15.

The reason for this change by Terraform is as follows: To help distribute the management of S3 bucket settings via independent resources, various arguments and attributes in the aws_s3_bucket resource have become read-only. Configurations dependent on these arguments should be updated to use the corresponding aws_s3_bucket_* resource. Once updated, new aws_s3_bucket_* resources should be imported into Terraform state.

So, I updated my code accordingly by following the guide here: Terraform AWS Provider Version 4 Upgrade Guide | S3 Bucket Refactor

The new working code looks like this:

I suspect this may have been an accident, though I prefer the new behavior.

The new behavior is a consequence of a change to how the bytecode for * arguments works. The change is in the changelog under Python 3.9.0 alpha 3:

bpo-39320: Replace four complex bytecodes for building sequences with three simpler ones.

The following four bytecodes have been removed:

• BUILD_LIST_UNPACK
• BUILD_TUPLE_UNPACK
• BUILD_SET_UNPACK
• BUILD_TUPLE_UNPACK_WITH_CALL

The following three bytecodes have been added:

• LIST_TO_TUPLE
• LIST_EXTEND
• SET_UPDATE

On Python 3.8, the bytecode for f(*a, a.pop()) looks like this:

I am also stuck with the same problem because I installed the latest version of Node.js (v17.0.1).

Just go for node.js v14.18.1 and remove the latest version just use the stable version v14.18.1

Cache misses. When N int objects are allocated back-to-back, the memory reserved to hold them tends to be in a contiguous chunk. So crawling over the list in allocation order tends to access the memory holding the ints' values in sequential, contiguous, increasing order too.

Shuffle it, and the access pattern when crawling over the list is randomized too. Cache misses abound, provided there are enough different int objects that they don't all fit in cache.

At r==1, and r==2, CPython happens to treat such small ints as singletons, so, e.g., despite that you have 10 million elements in the list, at r==2 it contains only (at most) 100 distinct int objects. All the data for those fit in cache simultaneously.

Beyond that, though, you're likely to get more, and more, and more distinct int objects. Hardware caches become increasingly useless then when the access pattern is random.

Illustrating:

The answer is in the PEP of the generator expressions, in particular the session Early Binding vs Late biding:

After much discussion, it was decided that the first (outermost) for-expression should be evaluated immediately and that the remaining expressions be evaluated when the generator is executed.

So basically the array in: