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Software: explore STEM content (page 23 of 25) · openstem

All fields Software Mathematics Physics Chemistry Biology Engineering Astronomy Environmental Other Software Software groups

Explore STEM Content

Search the community's STEM library — free to study, yours to make your own.

Software

Programming, algorithms and systems on openstem — flashcards, notes, quizzes, sketches and flowcharts shared by the community. Study free, or clone anything into your library.

Content Groups1

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Flashcards9 cards

How are generic functions declared in Go (1.18+)?1 / 9

With type parameters in square brackets before the argument list: `func Map[T, U any](s []T, f func(T) U) []U`. Constraints (like `any` or `comparable`) bound what types are allowed.

Software

Generics & Collections

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Generics & Collections

Collection2 items

01Concurrency

02Advanced Python

Software

Software · L4 · Python

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Software · L4 · Python

Note~119 words · 1 min

Not Every Test Runs at Every Gate A mature CI setup doesn't run the entire suite everywhere — it matches test speed to how often the gate fires, so fast feedback stays fast and thorough coverage still happens somewhere. Notice E2E tests run

Software

Software · L2 · Testing: CI Test Execution Strategy

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Software · L2 · Testing: CI Test Execution Strategy

Flashcards10 cards

What is the difference between `git merge` and `git rebase`?1 / 10

Merge creates a new merge commit preserving branch history. Rebase replays commits on top of another branch — rewrites commit history for a cleaner linear log. Never rebase shared/published commits.

Software

Core Concepts

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Core Concepts

Flashcards8 cards

What is the recurrence relation for merge sort?1 / 8

T(n) = 2T(n/2) + O(n). By the Master Theorem: O(n log n) time. It requires O(n) auxiliary space and is stable (preserves relative order of equal elements).

Software

Sorting Algorithms

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Sorting Algorithms

Flashcards10 cards

What five 'superpowers' does an `unsafe` block enable?1 / 10

Dereferencing raw pointers, calling unsafe functions/FFI, accessing/modifying mutable statics, implementing unsafe traits, and accessing union fields. `unsafe` does NOT turn off the borrow checker; it only permits these specific operations.

Software

Unsafe, FFI & Raw Pointers

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Unsafe, FFI & Raw Pointers

Note~207 words · 1 min

The Class NP A language L ⊆ {0,1}* is in NP if there exists a polynomial p and a polynomial-time deterministic verifier V such that for every x: NP-Hardness and NP-Completeness L is NP-hard if every language in NP reduces to L under polynom

Software

Software · L5 · NP-Completeness and Reductions

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Software · L5 · NP-Completeness and Reductions

Note~97 words · 1 min

Trigger, Render, Commit A re-render doesn't touch the screen right away. React first runs your component functions to build a new tree (the render phase), then compares it against the previous tree, and only afterwards mutates the real DOM

Software

Software · L1 · React: The Render Cycle

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Software · L1 · React: The Render Cycle

Flashcards10 cards

Why does Terraform need a state file?1 / 10

State maps configuration resources to real-world infrastructure IDs, tracks metadata and dependencies, and lets Terraform compute diffs for plans.

Software

State Management

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State Management

Collection4 items

01Fundamentals

02Threads & Processes

03Software · L1 · Concurrency: Protecting Shared State

+1 more

Software

Software · L1 · Concurrency

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Software · L1 · Concurrency

Note~119 words · 1 min

From Commit to Production A CI/CD pipeline is a chain of gates: each stage exists to catch a specific class of problem before it reaches the next, more expensive, stage. Test always runs before Package/Publish: it's cheaper to fail the pipe

Software

Software · L2 · Docker & Kubernetes: CI/CD Pipeline Stages

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Software · L2 · Docker & Kubernetes: CI/CD Pipeline Stages

Flashcards10 cards

What is the default index type in PostgreSQL?1 / 10

A B-tree index, which supports equality and range queries on ordered data and is the default for `CREATE INDEX`.

Software

Indexes & Query Planning

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Indexes & Query Planning

Quiz7 questions

What does an error budget primarily govern?

AThe monetary cost of running infrastructureBThe tradeoff between shipping risky changes and pausing to focus on reliabilityCHow many engineers are on the on-call rotationDThe salary budget for the SRE team

Software

Software · L4 · Site Reliability Engineering — 7 Q

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Software · L4 · Site Reliability Engineering — 7 Q

Collection4 items

01Kubernetes

02CI/CD Pipelines

03Software · L2 · Docker & Kubernetes: CI/CD Pipeline Stages

+1 more

Software

Software · L2 · Docker & Kubernetes

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Software · L2 · Docker & Kubernetes

Flowchart13 objects

Software

Software · L2 · Docker & Kubernetes: CI/CD Pipeline Stages · flowchart

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Software · L2 · Docker & Kubernetes: CI/CD Pipeline Stages · flowchart

Collection4 items

01Software · L5 · Cryptographic Foundations

02Software · L5 · Theoretical Cryptography: Hardness, Pseudorandomness, and Proof

03Software · L5 · The Cryptographic Primitive Hierarchy

+1 more

Software

Software · L5 · Cryptographic Foundations

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Software · L5 · Cryptographic Foundations

Flashcards8 cards

How does a typical backtracking regex engine try to match a pattern?1 / 8

It tries alternatives and quantifier repetitions greedily, and when a later part of the pattern fails to match, it backtracks — undoing the most recent choice and trying the next alternative — until a match is found or all options are exhausted.

Software

Regular Expressions & Text Parsing

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Regular Expressions & Text Parsing

Quiz3 questions

What is an algorithm?

AA type of computerBA step-by-step list of instructionsCA picture drawn by a robotDA very fast calculator

Software

Software · L1 · Algorithms and Sequencing

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Software · L1 · Algorithms and Sequencing

Quiz5 questions

Why does the Test stage run before Package/Publish?

ATests run faster after publishingBIt's cheaper to fail fast on broken code than to publish a bad artifact firstCPublishing requires test results as input dataDThere is no required order between the two

Software

Software · L2 · Docker & Kubernetes: CI/CD Pipeline Stages

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Software · L2 · Docker & Kubernetes: CI/CD Pipeline Stages

Flashcards10 cards

What is destructuring assignment?1 / 10

Syntax to unpack values from arrays or properties from objects into variables. `const {a, b} = obj` and `const [x, y] = arr`. Supports defaults and renaming: `const {a: renamed = 0} = obj`.

Software

ES6+ Features

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ES6+ Features

Flashcards10 cards

What is a branded type and how do you create one?1 / 10

A branded (nominal) type uses an intersection with a phantom tag to prevent accidental substitution of structurally identical types: `type UserId = string & { readonly _brand: 'UserId' }`. Only created via a factory, not assignable from plain string.

Software

Advanced Patterns

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Advanced Patterns

Quiz8 questions

Which of these HTTP methods is idempotent but not safe?

AGETBPOSTCPUTDOPTIONS

Software

Software · L3 · API Design & REST

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Software · L3 · API Design & REST

Note~560 words · 3 min

How a Backtracking Engine Matches Most mainstream regex engines (PCRE, Python's re, JavaScript's RegExp) are backtracking engines: they try the pattern against the input greedily, and whenever a later part fails to match, they backtrack to

Software

Software · L3 · Regular Expressions & Text Parsing

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Software · L3 · Regular Expressions & Text Parsing

Flashcards8 cards

How does the cache-aside (lazy loading) pattern work?1 / 8

The application checks the cache first; on a miss, it reads from the database, then writes the result into the cache before returning it. Subsequent reads for the same key hit the cache until it expires or is evicted.

Software

Caching Strategies

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Caching Strategies

Flashcards7 cards

Distinguish data parallelism from model parallelism in distributed training.1 / 7

Data parallelism replicates the full model on every worker; each worker computes gradients on a distinct shard of a mini-batch, and gradients are aggregated (e.g. by summing/averaging) before the shared parameters are updated. Model parallelism instead partitions the model itself across workers — different workers hold different layers or tensor slices — because the model is too large to fit in one device's memory, and activations must be passed between workers as they flow through the partitioned computation graph.

Software

Software · L5 · Distributed Machine Learning Systems

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Software · L5 · Distributed Machine Learning Systems

Flashcards9 cards

What is time complexity O(log n) and which algorithms exhibit it?1 / 9

O(log n) means the work halves with each step. Binary search, balanced BST operations, and heap insert/extract all run in O(log n). Typically achieved by halving the problem size at each step.

Software

Big-O & Complexity

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Big-O & Complexity

Flashcards7 cards

Define a Turing machine as a formal tuple.1 / 7

A Turing machine is M = (Q, Σ, Γ, δ, q₀, q_accept, q_reject) where Q is a finite state set, Σ is the input alphabet, Γ ⊇ Σ is the tape alphabet (including a blank symbol ⊔ ∉ Σ), δ: Q × Γ → Q × Γ × {L, R} is the transition function, q₀ is the start state, and q_accept, q_reject ∈ Q are distinguished halting states. M operates on a semi-infinite tape with a read/write head; each step reads the symbol under the head, writes a symbol, moves the head, and changes state.

Software

Software · L5 · Computability Theory

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Software · L5 · Computability Theory

Note~112 words · 1 min

Sending a Message Across the Internet When you send a message or open a website, your computer breaks the information into small pieces called packets. Each packet travels through a network of routers — special computers that act like post

Software