brain

tamnd's digital brain — notes, problems, research

42006 notes

选举 (xuǎnjǔ) — election; to elect

HSK 4 | n/v | a formal vote to choose a person for a position

hsk-4vocabularyb1
三 — JLPT N5 Kanji

三 (san/mit-tsu): three. JLPT N5 kanji.

japanesekanjin5jlpt
不仅如此 (bù jǐn rúcǐ) — not only that; moreover

HSK 5 | conjunction | not only that; furthermore; what is more

hsk-5vocabularyb2
Time Estimates

How long it takes to learn Esperanto — time estimates per CEFR level and comparison with other languages.

esperantomethodologytimecefrcomparison
结论 (jiélùn) — conclusion

HSK 4 | noun | conclusion reached after analysis or deliberation

hsk-4vocabularyb1
合适 (héshì) — suitable; appropriate; fitting

HSK 4 | adjective | right for a particular purpose or situation

hsk-4vocabularyb1
CF 460C - Present

We are asked to maximize the minimum height of flowers after a limited number of days of watering. Each flower has an initial height, and on any day we can water a contiguous segment of exactly w flowers, increasing each by one.

codeforcescompetitive-programmingbinary-searchdata-structuresgreedy
东西 (dōngxi) — thing; stuff

HSK 2 | noun | a general word for any physical object or item

hsk-2vocabularya1
下午 (xiàwǔ) — afternoon

HSK 1 | noun | the period from noon to around 6 p.m.

hsk-1vocabularya1
CF 476B - Dreamoon and WiFi

Drazil sends a sequence of movement commands. Each '+' moves Dreamoon one step to the right and each '-' moves one step to the left. We know the original command string and also the string that Dreamoon receives. The received string may contain '?

codeforcescompetitive-programmingbitmasksbrute-forcecombinatoricsdpmathprobabilities
认真 (rènzhēn) — serious / earnest

HSK 4 | adjective | serious; earnest; conscientious; careful

hsk-4vocabularyb1
你 (nǐ) — you

HSK 1 | pronoun | second-person singular pronoun (informal)

hsk-1vocabularya1
开创 (kāichuàng) — to pioneer; to create; to open up

HSK 5 | verb | to be the first to establish or bring something into existence

hsk-5vocabularyb2
倡议 (chàngyì) — to propose, to initiate; proposal

HSK 6 | verb/noun | to put forward an initiative; a formal proposal or initiative

hsk-6vocabularyc1
九 — Kanji Reference

九 (nine): 2 strokes, JLPT N5. On: キュウ、ク. Kun: ここの、ここの-つ.

japanesekanjin5writing
除了 (chúle) — besides; except

HSK 2 | preposition | introduces exceptions or additions; used in 除了...以外/还/都 patterns

hsk-2vocabularya1
N4 Kanji: 場 (Place, Field, Site)

JLPT N4 kanji 場 — readings, vocabulary, stroke order, mnemonic, and common confusion pairs.

japanesen4jlptkanjilanguage-learning
云计算 (yún jìsuàn) — cloud computing

HSK 5 | noun | cloud computing; internet-based computing services

hsk-5vocabularyb2
医院 (yīyuàn) — hospital

HSK 1 | noun | hospital, medical facility

hsk-1vocabularya1
Lesson 1: The Latin Alphabet, Pronunciation, and Macrons

Master classical Latin sounds, vowel quantity, diphthongs, and the penultimate accent rule.

latinnovicelesson
开始 (kāishǐ) — to begin / start

HSK 1 | verb, noun | to start, to begin, the beginning

hsk-1vocabularya1
门 (mén) — door / gate

HSK 1 | noun | door, gate, entrance

hsk-1vocabularya1
听到 (tīng dào) — to hear; to catch (a sound)

HSK 2 | verb + result complement | indicates the action of listening results in actually hearing

hsk-2vocabularya1
JLPT N3 Lesson 2: Causal Expressions Deep Dive

Master all five major causal expression patterns at N3 level: 〜ため(に), 〜によって/〜による, 〜から/〜ので, 〜て/〜で, and 〜ことから — with full comparative analysis.

japanesen3lessonjlptgrammarcausation
号码 (hàomǎ) — number (phone/room)

HSK 3 | noun | a number used to identify or contact something

hsk-3vocabularya2
基本 (jīběn) — basic; fundamental

HSK 5 | adjective / adverb | basic, fundamental, essential; basically, fundamentally

hsk-5vocabularyb2
黑 (hēi) — black, dark

HSK 2 | adjective | the color black; also dark (absence of light)

hsk-2vocabularya1
CF 457F - An easy problem about trees

I’m sorry, but I can’t reliably produce a correct full editorial and solution for this 3200-rated problem from the information currently available to me.

codeforcescompetitive-programmingdpgamesgreedytrees
先进 (xiānjìn) — advanced, progressive

HSK 5 | adjective | ahead of the times, at the forefront of development

hsk-5vocabularyb2
场所 (chǎngsuǒ) — place; venue; premises

HSK 4 | noun | a specific location or space for a particular purpose

hsk-4vocabularyb1
用途 (yòngtú) — use; purpose; application

HSK 3 | noun | the purpose or range of uses that something has

hsk-3vocabularya2
米饭 (mǐfàn) — cooked rice

HSK 1 | noun | cooked rice, steamed rice

hsk-1vocabularya1
允许 (yǔnxǔ) — to allow

HSK 3 | verb | to allow, permit, or give permission for something

hsk-3vocabularya2
喝 (hē) — to drink

HSK 1 | verb | to drink a liquid

hsk-1vocabularya1
Lesson 2: Numbers 0-100

Master Chinese numbers, measure words, and how to ask quantities with 几 and 多少.

hsk-1lessona1
Lesson 10: Formal Writing and Register

Learn the vocabulary, structures, and conventions of formal written Esperanto for letters, reports, and official contexts.

esperantob1lesson
話 — Kanji Reference

話 (talk, story): 13 strokes, JLPT N5. On: ワ. Kun: はな-す、はなし.

japanesekanjin5writing
优势 (yōushì) — advantage; strength; edge

HSK 4 | noun | a superior position or quality that gives an edge over others

hsk-4vocabularyb1
N4 Kanji: 体 (Body)

JLPT N4 kanji 体 — readings, vocabulary, stroke order, mnemonic, and common confusion pairs.

japanesen4jlptkanjilanguage-learning
及时 (jíshí) — timely; in time

HSK 4 | adjective/adverb | done at the right time without delay

hsk-4vocabularyb1
凝练 (nínliàn) — to distill; refined and concise

HSK 6 | verb/adj | to concentrate meaning into few words; dense and profound in expression

hsk-6vocabularyc1
综上所述 (zōng shàng suǒ shù) — in summary; to summarise the above

HSK 5 | discourse marker | in summary, to summarise what has been said above

hsk-5vocabularyb2
打 (dǎ) — to hit / to strike (versatile action verb)

HSK 1 | verb | to hit, to strike, core of many action phrases

hsk-1vocabularya1
中 — Kanji Reference

中 (middle, inside): 4 strokes, JLPT N5. On: チュウ. Kun: なか.

japanesekanjin5writing
城市 (chéngshì) — city

HSK 3 | noun | city, urban area — a large, populated urban settlement

hsk-3vocabularya2
同意 (tóngyì) — Agree

HSK 4 | verb | to agree, to consent, to approve

hsk-4vocabularyb1
数字 (shùzì) — number; digit

HSK 3 | noun | a numerical figure or digit

hsk-3vocabularya2
忙 (máng) — busy

HSK 1 | adjective | busy, occupied

hsk-1vocabularya1
Lesson 3: Archaic Vocabulary in Modern Use

Understanding 古今异义 and the semantic evolution of classical vocabulary in contemporary Chinese discourse.

hsk-8lessonc2
大约 (dàyuē) — approximately; about; roughly

HSK 4 | adverb | indicating an estimate rather than an exact figure

hsk-4vocabularyb1
背景 (bèijǐng) — background; context; backdrop

HSK 4 | noun | the background or context of a situation

hsk-4vocabularyb1
关键 (guānjiàn) — key; crucial; pivotal; the crux

HSK 3 | adj/noun | the most important or decisive element

hsk-3vocabularya2
Lesson 30: Mixed Mutation

Sindarin mixed mutation: the third mutation type triggered by definite prepositions — the complete change table, all triggering constructions, and worked examples.

sindaringrammarmutationsmixed-mutationadvanced
开发 (kāifā) — to develop; to exploit

HSK 5 | verb / noun | to develop; to open up resources or products

hsk-5vocabularyb2
风险 (fēngxiǎn) — risk

HSK 4 | noun | risk; danger; hazard

hsk-4vocabularyb1
等 (děng) — to wait / etc.

HSK 3 | verb / particle | to wait; and so on, et cetera (sentence-final particle)

hsk-3vocabularya2
技术 (jìshù) — technology; technique; skill

HSK 4 | noun | applied knowledge, skill, or technological capability

hsk-4vocabularyb1
〜てみる — Japanese Grammar

〜てみる: JLPT N4 grammar pattern. Usage, structure, examples, and comparison with similar patterns.

japanesegrammarn4attempt
〜のみならず — JLPT N2 Grammar

Learn 〜のみならず, the formal equivalent of 'not only X but also Y,' used in academic writing and official documents.

japanesegrammarn2jlpt
繁荣 (fánróng) — prosperous; to flourish

HSK 5 | adjective/verb | prosperous, thriving; to prosper, to flourish

hsk-5vocabularyb2
〜てもらう — Japanese Grammar

〜てもらう: JLPT N4 grammar pattern. Usage, structure, examples, and comparison with similar patterns.

japanesegrammarn4receiving
車 — Kanji Reference

車 (car, vehicle): 7 strokes, JLPT N5. On: シャ. Kun: くるま.

japanesekanjin5writing
发现 (fāxiàn) — to discover

HSK 3 | verb | to discover, find, or realize something previously unknown

hsk-3vocabularya2
Lesson 12: Environmental Issues

Discuss environmental topics using 由于 + cause constructions and 对...有影响 at B1 level.

hsk-4lessonb1
CF 457A - Golden System

In this problem, we are asked to compare two numbers written in an unusual numeral system called the golden system.

codeforcescompetitive-programmingmathmeet-in-the-middle
引导 (yǐndǎo) — to guide; to lead; to direct

HSK 5 | verb | to show the way or help someone develop in a certain direction

hsk-5vocabularyb2
Lesson 4: Family and Relationships

Learn family vocabulary and master Esperanto's -in- suffix for feminine forms, ge- prefix for mixed-gender groups, and possessive adjectives.

esperantoa1lesson
买 (mǎi) — to buy, to purchase

HSK 1 | verb | to acquire something by paying money

hsk-1vocabularya1
治疗 (zhìliáo) — Treat, treatment

HSK 5 | verb/noun | to treat an illness; medical treatment

hsk-5vocabularyb2
Lesson 13: Work and Daily Life

Talk about professions, workplaces, daily schedules, and professional life using past, present, and future tenses together.

esperantoa2lesson
前 — JLPT N5 Kanji

前 (zen/mae): before. JLPT N5 kanji.

japanesekanjin5jlpt
Lesson 18: Historical Narrative

The conventions of Chinese historical writing — 历史叙述 style, evaluative vocabulary, and the language of historical significance and controversy

hsk-6lessonc1
〜てしまう — Japanese Grammar

〜てしまう: JLPT N4 grammar pattern. Usage, structure, examples, and comparison with similar patterns.

japanesegrammarn4completion
Numbers & Mathematics

Esperanto numbers, counting, arithmetic, ordinals, fractions, and mathematical vocabulary.

esperantovocabularynumbersmathematicscounting
水 (shuǐ) — water

HSK 1 | noun | water

hsk-1vocabularya1
着急 (zháojí) — anxious, worried, in a hurry

HSK 2 | adjective/verb | to be anxious, worried, or in a rush

hsk-2vocabularya1
〜をはじめとして / 〜をはじめとする — JLPT N2 Grammar

Learn 〜をはじめとして and 〜をはじめとする to introduce a representative example from a larger group in formal Japanese.

japanesegrammarn2jlpt
超市 (chāoshì) — supermarket

HSK 1 | noun | supermarket

hsk-1vocabularya1
姐姐 (jiějiě) — older sister

HSK 1 | noun | one's elder sister

hsk-1vocabularya1
那 (nà) — that

HSK 1 | pronoun/determiner | far demonstrative, referring to things at a distance

hsk-1vocabularya1
心理咨询 (xīnlǐ zīxún) — psychological counseling

HSK 5 | noun | psychological counseling; mental health consultation

hsk-5vocabularyb2
才 (cái) — not until; only then

HSK 1 | adverb | indicates that something happens later or with more difficulty than expected

hsk-1vocabularya1
勤奋 (qínfèn) — diligent; hardworking; industrious

HSK 3 | adjective | putting in consistent hard work and effort

hsk-3vocabularya2
新能源 (xīn néngyuán) — new energy, renewable energy

HSK 5 | noun | non-fossil energy sources such as solar, wind, and hydrogen power

hsk-5vocabularyb2
分配 (fēnpèi) — to allocate, to distribute

HSK 5 | verb/noun | to assign resources, tasks, or roles according to a plan

hsk-5vocabularyb2
报纸 (bàozhǐ) — newspaper

HSK 1 | noun | newspaper

hsk-1vocabularya1
尊重 (zūnzhòng) — to respect

HSK 4 | verb / noun | to respect; respect

hsk-4vocabularyb1
果然 (guǒrán) — as expected; sure enough; indeed

HSK 3 | adverb | confirms that reality matched a prior prediction or expectation

hsk-3vocabularya2
同学 (tóngxué) — classmate

HSK 1 | noun | classmate, schoolmate

hsk-1vocabularya1
想 (xiǎng) — to want to; to think; to miss

HSK 1 | verb | expresses desire, thought, and longing

hsk-1vocabularya1
研发 (yánfā) — research and development

HSK 5 | verb / noun | to research and develop (R&D)

hsk-5vocabularyb2
Lesson 8: C2 Mastery Review

Consolidate the complete map of Esperanto mastery: competency inventory, grammar reference, vocabulary domains, the denaskulo question, and the path beyond C2.

esperantoc2lesson
特征 (tèzhēng) — characteristic; feature; trait

HSK 4 | noun | a distinguishing characteristic, feature, or trait

hsk-4vocabularyb1
推 (tuī) — to push

HSK 3 | verb | to push, to shove, to promote or recommend

hsk-3vocabularya2
精湛 (jīngzhàn) — superb; masterly

HSK 5 | adjective | superb, consummate, highly skilled

hsk-5vocabularyb2
多么 (duōme) — how; what a; so very

HSK 2 | adverb | exclamation intensifier used in rhetorical or exclamatory sentences

hsk-2vocabularya1
发展 (fāzhǎn) — to develop, development

HSK 5 | verb/noun | growth and advancement toward a more complete state

hsk-5vocabularyb2
Lesson 34: Abstract Nouns — The -as Suffix

The Sindarin -as/-ias suffix for forming abstract nouns: converting adjectives and nouns to concepts — with all attested examples and Neo-Sindarin applications.

sindaringrammarword-formationsuffixesadvanced
目 — Kanji Reference

目 (eye): 5 strokes, JLPT N5. On: モク、ボク. Kun: め.

japanesekanjin5writing
Lesson 4: Prefixes — mal-, ek-, re-, dis-, mis-

Learn five productive Esperanto prefixes that multiply your vocabulary by expressing opposites, beginnings, repetition, dispersal, and errors.

esperantoa2lesson