macOS · Windows v0.30.0

One workspace for each course

Open an existing study folder as a course, then use notes, PDFs, the browser, AI tutor, and whiteboard in tabs and split views. Your board and calendar stay in the same window.

Download for Mac

v0.30.0 · Free · MIT licensed

반달 AI
안녕하세요. 자료구조 과목의 자료를 읽고 있어요. 지금 열려 있는 03-해시테이블.pdf와 중간고사-정리.md를 근거로 답할 수 있어요.

12 / 38

100%

형광펜 주석 0

자료구조 · 3주차

해시 테이블과 충돌

해시 함수는 임의 길이의 키를 고정된 범위의 정수로 사상한다.

3. 충돌 해결

서로 다른 키가 같은 버킷을 가리킬 때 충돌이 발생한다.

체이닝은 각 버킷에 연결 리스트를 두어 충돌을 해결한다.

개방 주소법은 비어 있는 다음 위치를 찾아 값을 저장한다.

문장을 눌러 형광펜으로 칠해보세요 · 03-해시테이블.pdf

중간고사-정리.md 저장됨

자료구조 중간고사 정리

해시 테이블은 키를 배열 인덱스로 바꿔 평균 O(1) 조회를 만든다. 충돌을 어떻게 처리하느냐가 사실상 전부다.

충돌 해결

체이닝 — 버킷마다 연결 리스트를 둔다
개방 주소법 — 비어 있는 다음 칸을 탐색한다

적재율이 0.75를 넘으면 재해싱한다.

선형 조사는 군집화가 생기므로 이차 조사나 이중 해싱을 함께 본다.

Not a screenshot — a working window. Open and close tabs, press the formatting buttons, highlight the PDF, ask the AI tutor. The app’s interface is Korean.

COURSE WORKSPACE

Choose a course and its desk opens

Each course is an actual folder you were already studying in. Group courses by semester and arrange them by dragging; each opens with its own tab layout and material panel.

01

Your existing folder is the course

Open a folder on your computer without moving it into a dedicated path, group it by semester, and drag courses into order.
02

A tab workspace per course

Open notes, PDFs, the browser, AI tutor, and whiteboard as tabs, split the view, and pin favorite tabs.
03

Bring in material and search fast

Drag from Finder or paste with ⌘V, then create folders and drag items into place. ⌘P finds files; ⇧⌘F searches their contents.
04

Learn in the real interface

The interactive tutorial creates a temporary course and teaches courses, tabs, and material organization in the actual UI.

03-해시테이블.pdf

자료구조~/학교/2026-1/자료구조

과목을 다시 열면 이 탭 배치를 이어갑니다.

◐

The course rail and material tree with 자료구조 selected.

READ · MARK · WRITE

Read the lecture with your notes beside it

The PDF stays paper-white while the app chrome recedes. Mark a passage, keep it as a note, and organize the result in a Markdown file in the same workspace.

Read a PDF and keep the passage

Scroll through pages, highlight in four colors, or write with a pen. A selected quote stays with its page in the annotation rail and can be sent to the AI tutor.

자료구조 · 03

해시 테이블과 충돌 해결

키를 배열의 위치로 바꾸면 평균적으로 빠른 탐색이 가능하다.

Separate chaining

같은 위치로 계산된 원소를 연결 리스트에 이어 붙인다. 적재율이 높아질수록 탐색에 필요한 비교 횟수도 늘어난다.

해시 함수는 같은 키에 대해 언제나 같은 위치를 반환해야 한다.

테이블 크기와 해시 함수, 충돌 해결 방식은 데이터의 성격에 맞춰 함께 선택한다.

A white PDF page, highlights, a quoted note, and the page-grouped annotation rail.

Write in an ordinary .md file

The Milkdown WYSIWYG editor autosaves as you type. If the file changes on disk, Bandal asks whether to reload it or keep the current content.

¶H1H2H3BIS•≡1.❝<>

자료구조 중간고사 정리

3주차 · 해시 테이블

해시 테이블은 키를 배열의 인덱스로 변환해 데이터를 저장한다. 평균 탐색 시간은 O(1)이지만 충돌 처리 방식에 따라 실제 비용이 달라진다.

충돌 해결

체이닝: 같은 버킷의 원소를 연결한다.
개방 주소법: 규칙에 따라 다른 빈 버킷을 찾는다.
적재율이 높아지기 전에 테이블 크기를 늘린다.

같은 키는 항상 같은 해시 값을 가져야 한다.

복습할 것

평균·최악 시간 복잡도 비교

선형 조사 예제 다시 풀기

A Markdown note with its filename and save state at the top.

STUDY BOARD

See assignments, to-dos, and schedules at a glance

Move cards across the To do, In progress, and Done kanban, then check schedules on the calendar. Course colors and due badges distinguish each class and deadline.

Filter by course
Due-date badges
Drag between states
Calendar schedules

할 일

해시 테이블 연습문제 1–6번

행렬식 과제 제출

진행 중

중간고사 요약 노트 만들기

프로세스 스케줄링 복습

완료

3주차 강의자료 읽기

A kanban board collecting assignments and to-dos from multiple courses.

OPTIONAL AI TUTOR

Connect Claude Code or Codex inside a course

Choose Claude Code or the Codex (GPT) CLI installed on your computer and run it in the course folder. The tutor reads course material to answer, and can create material or manage the board in the app.

Use your existing Claude or ChatGPT subscription without a separate API key. Open multiple conversation tabs per course and resume from the previous-conversation list.

Call it anywhere from the floating Bandal orb. Destructive actions ask first, and Bandal provides a change list and undo.

해시 테이블에서 충돌이 생기는 이유를 지금 열린 자료 기준으로 설명해 줘.

파일 읽음 강의자료/03-해시테이블.pdf 12쪽

해시 함수가 만들 수 있는 인덱스 수보다 키의 경우가 훨씬 많기 때문에, 서로 다른 키가 같은 인덱스로 계산될 수 있습니다. 이것이 충돌입니다.

열린 자료에서는 같은 버킷에 원소를 이어 붙이는 체이닝을 먼저 설명합니다. 적재율이 높아지면 한 버킷에서 비교할 원소가 늘어나므로 평균 탐색 비용도 커집니다.

자료구조에 대해 물어보세요

The Korean-first AI tutor showing a conversation and a file-read tool activity card.

CONTEXT TOOLS

Keep the places around a course close, too

Keep school-site shortcuts, the built-in browser, and groups with friends close to the course workspace.

A reconstruction of the real browser chrome showing a synthetic school-service page.

School-site shortcuts

Choose your school to place portal, LMS, library, and similar shortcuts above the course rail.

A built-in browser that remembers sign-ins

Open school sites and web material as tabs, save sign-in details, and autofill them on the next visit.

Together with Google sign-in

Create a group with friends to chat and share whiteboards and notes. Join directly with an invite code.

APPEARANCE

Six themes for different study conditions

Each palette is made for a different condition: a bright classroom, an unlit room, long PDF reading, harsh light or projection, and color-reduced focus.

Under the app contrast contract, body text clears 4.5:1 on all three surfaces and black PDF text clears 4.5:1 over every highlight.

APPEARANCE

테마

반달 다크Night-sky navy and moon gold. The default theme.
반달 라이트Ivory paper for daylight and bright classrooms.
자정True black for unlit rooms and OLED displays.
세피아Warm paper that reduces glare during long PDF sessions.
고대비Clear boundaries for low vision, harsh light, and projectors.
흑연An achromatic mode that leaves color to the material.

Reconstructed from the Appearance screen in v0.30.0 Settings. The app UI remains Korean.

DATA & RELEASE

Separate what stays on disk from what is sent

Bandal v0.30.0 is free MIT-licensed software. Local study files, requests through your chosen AI CLI, and Together data follow different paths.

Course files: A course is an actual folder on your computer; its material and saved school sign-in details remain on the device.
AI tutor: Prompts and course context are processed through your chosen Claude Code or Codex CLI. A Bandal server does not proxy the request.
Together: Together is the only feature that goes through a server. It syncs Google sign-in, groups, chat, shared whiteboards, and shared notes.
Distribution: Bandal supports macOS on Apple Silicon and Intel plus Windows x64, with automatic updates. macOS is signed and notarized; the Windows installer is not yet signed.

FAQ

What to know before installing

What does the AI tutor require?

Install and sign in to Claude Code or the Codex CLI, then choose the engine. Bandal uses your existing Claude or ChatGPT subscription without a separate API key.

Where are course files stored?

They remain in the actual folder on your computer that you selected as the course. Drag material in from Finder, paste it, or create folders to organize it.

What is sent when I use the AI tutor?

Prompts and course context you send are processed through your chosen Claude Code or Codex CLI. A Bandal server does not proxy the request.

What can I do with Together?

After Google sign-in, join a group by invite code to chat and share whiteboards and notes. Only Together data goes through a server.

Which installers are available?

Bandal provides macOS dmg files for Apple Silicon and Intel, and a Windows x64 exe, with automatic updates after installation. There is no Linux or Windows arm64 build.

Will Windows show a warning?

The Windows installer is not code-signed yet, so SmartScreen may show an unknown-publisher warning. The macOS builds are Developer ID signed and Apple-notarized.

What does 반달 mean?

The whole circle is a semester and the filled half is the studying completed so far. The mark keeps the unlit half as a thin ring instead of cutting it away like a crescent.

One workspace for each course

해시 테이블과 충돌

3. 충돌 해결

3.1 분리 연쇄법

평균 탐색 비용

3.2 개방 주소법

자료구조 중간고사 정리

충돌 해결

Your existing folder is the course

A tab workspace per course

Bring in material and search fast

Learn in the real interface

Read a PDF and keep the passage

Write in an ordinary .md file

See assignments, to-dos, and schedules at a glance

Connect Claude Code or Codex inside a course

School-site shortcuts

A built-in browser that remembers sign-ins

Together with Google sign-in

Six themes for different study conditions

Download Bandal v0.30.0