Chertov & Vorobyov physics problem solutions

One solved problem, in full. Address it either with paragraph + number, or with label — the spoken form "1.12" (a dot, a dash or a space also work: "1-12", "1 12"). Returns JSON: when found, {found: true, problem: {label, paragraph, number, chapter, condition, solution_image_url, page_url, chapter_name, paragraph_name, chapter_url, paragraph_url, solution_format}}; otherwise {found: false, reason: "not_solved"|"not_found", label, paragraph, number, message}. A missing or unsolved problem is a normal result, not an error — do not retry it.

Map of the whole corpus: every chapter of the Chertov & Vorobyov physics problem book, with its paragraph (§) numbers and how many solved problems it holds. Takes no arguments. Returns JSON: {chapters: [{chapter, name, paragraph_count, paragraphs, paragraph_range, solved_problem_count, page_url}], totals: {chapters, paragraphs, solved_problems}}. Call this first to learn the shape of the corpus.

Paragraphs (§) of the problem book, optionally restricted to one chapter. Arguments: chapter (optional integer). Returns JSON: {chapter, paragraphs: [{paragraph, name, chapter, chapter_name, solved_problem_count, problem_number_range, page_url}], totals: {paragraphs, solved_problems}}. Paragraph numbers are unique across the whole book, so a paragraph number alone addresses a section.

Solved problems of one paragraph (§), paginated and in book order. Arguments: paragraph (required integer), page (optional, default 1), per_page (optional, default 25, max 100). Returns JSON: {paragraph, paragraph_name, chapter, chapter_name, problems: [{label, paragraph, number, chapter, condition, solution_image_url, page_url}], pagination: {page, per_page, total, total_pages}}. `condition` is the problem statement as plain Russian text; the worked solution exists only as the GIF at `solution_image_url`. Problems without a solution are not listed and are not counted.

Full-text search over the Russian problem statements. Searches PROBLEMS ONLY — never articles or news. Arguments: query (required string, at least 5 characters once whitespace is removed), page (optional, default 1), per_page (optional, default 25, max 100). Returns JSON: {query, problems: [{label, paragraph, number, chapter, condition, solution_image_url, page_url}], pagination: {page, per_page, total, total_pages}}. Query in Russian — the statements are Russian. A shorter query is rejected with a validation error rather than returning nothing, and LIKE wildcards in the query are matched literally.