In-Memory SQL with CSV Initialization

Problem: Implement a Simplified In-Memory SQL Engine (with CSV Initialization) Implement an in-memory database that can initialize a table from a CSV string and execute a few SQL-like operations. Input Read from stdin: Line 1: a CSV string csv (may contain quotes/escapes) representing the table Line 2: integer q, the number of subsequent commands Next q lines: one command per line CSV Rules The CSV encodes a 2D table: First row contains column names Remaining rows are data rows Fields are separated by commas A field may be wrapped in double quotes " When quoted, the field may contain commas Inside a quoted field, "" represents a literal double quote character " You must implement parse_csv(csv: str) -> List[List[str]] yourself. Supported Commands (minimum viable subset) SELECT <col1,col2,...> WHERE <col>=<value> Filter rows by equality condition Output selected columns joined by commas, one row per line INSERT <comma-separated-values> Insert one row (must match the number of columns) DELETE WHERE <col>=<value> Delete all rows matching the equality condition Output Print results for each SELECT. Other commands produce no output. Constraints Total rows and commands up to 1e5 Aim for good time complexity Sample Tests (see Chinese version) Example Input name,age,city 3 SELECT name WHERE city=New York INSERT "Charlie",22,"New York" SELECT name,age WHERE city=New York Output Alice Alice,30 Charlie,22