add flashcard generation tooling and binary search cards

- gen-flashcards.py: auto-generate recognition cards from all problem files - toolkit/gen-problem-cards.org: 199 auto-generated problem cards - 5 binary search tool cards (std::binary_search, std::lower_bound, comparison, two-sum pattern, sorting gotcha) - two-sum.org: add binary search C++ attempt - lc-org.el: add doom emacs localleader keybinding support
2026-06-08 01:28:25 +08:00
parent c67841fe07
commit e10cc4257d
9 changed files with 2052 additions and 9 deletions
@@ -0,0 +1,158 @@
+#!/usr/bin/env python3
+"""Auto-generate Anki flashcards from problem .org files.
+
+Generates one recognition card per problem:
+  Front: Problem number + name
+  Back:  Problem statement (first paragraph)
+"""
+
+import re
+import sys
+from pathlib import Path
+
+BASE = Path(__file__).parent
+DSA = BASE / "dsa"
+OUTPUT = BASE / "toolkit" / "gen-problem-cards.org"
+
+TOPIC_DISPLAY = {
+    "1-d-dynamic-programming": "1D DP",
+    "2-d-dynamic-programming": "2D DP",
+    "advanced-graphs": "Advanced Graphs",
+    "arrays-hashing": "Arrays & Hashing",
+    "backtracking": "Backtracking",
+    "binary-search": "Binary Search",
+    "bit-manipulation": "Bit Manipulation",
+    "graphs": "Graphs",
+    "greedy": "Greedy",
+    "heap-priority-queue": "Heap / Priority Queue",
+    "intervals": "Intervals",
+    "linked-list": "Linked List",
+    "math-geometry": "Math & Geometry",
+    "sliding-window": "Sliding Window",
+    "stack": "Stack",
+    "trees": "Trees",
+    "tries": "Tries",
+    "two-pointers": "Two Pointers",
+}
+
+
+def parse_file(path: Path) -> dict | None:
+    """Extract problem metadata and statement from an .org file."""
+    text = path.read_text()
+
+    # Match heading: * TODO 0217. Contains Duplicate :easy:
+    m = re.search(
+        r"^\* (?:TODO|DONE) (\d{4})\. (.+?) :(easy|medium|hard):",
+        text,
+        re.MULTILINE,
+    )
+    if not m:
+        return None
+
+    num = m.group(1)
+    name = m.group(2).strip()
+    difficulty = m.group(3)
+
+    # Topic = parent directory name
+    topic_slug = path.parent.name
+    topic = TOPIC_DISPLAY.get(topic_slug, topic_slug.replace("-", " ").title())
+
+    # Problem statement: first non-empty, non-heading, non-property line after :END:
+    after_props = text[m.end():]
+    lines = after_props.split("\n")
+    statement_lines = []
+    in_block = False
+    for line in lines:
+        stripped = line.strip()
+        if stripped == ":END:":
+            continue
+        if not stripped:
+            if statement_lines:
+                break
+            continue
+        if stripped.startswith("#+") or stripped.startswith("*") or stripped.startswith(":"):
+            if statement_lines:
+                break
+            continue
+        statement_lines.append(stripped)
+
+    statement = " ".join(statement_lines).strip()
+    # Clean up org markup for plain text
+    statement = re.sub(r"[~=*/_]", "", statement)
+
+    return {
+        "num": num,
+        "name": name,
+        "difficulty": difficulty,
+        "topic": topic,
+        "statement": statement,
+        "path": path,
+    }
+
+
+def generate_cards(problems: list[dict]) -> str:
+    """Generate org-mode flashcard content."""
+    parts = []
+    parts.append("#+TITLE: Auto-Generated Problem Cards")
+    parts.append("#+ANKI_DECK: study_deck_02")
+    parts.append("")
+
+    for p in sorted(problems, key=lambda x: int(x["num"])):
+        num = p["num"]
+        name = p["name"]
+        diff = p["difficulty"]
+        topic = p["topic"]
+        stmt = p["statement"]
+
+        # Card: given problem name → what does it ask?
+        title = f"LC {num}. {name} — what does it ask?"
+        tags = f":leetcode:{diff}:{topic.replace(' ', '-').lower()}:retrieval::recognition:"
+
+        parts.append(f"* {title} {tags}")
+        parts.append(":PROPERTIES:")
+        parts.append(":ANKI_NOTE_TYPE: Basic")
+        parts.append(":END:")
+        parts.append("** Front")
+        parts.append(f"What does LeetCode {num} *{name}* ask you to do?")
+        parts.append("** Back")
+        parts.append(stmt)
+        parts.append("")
+
+    return "\n".join(parts)
+
+
+def main():
+    dry_run = "--dry-run" in sys.argv
+
+    org_files = sorted(DSA.rglob("*.org"))
+    org_files = [f for f in org_files if f.name != "udfs.org"]
+    print(f"Found {len(org_files)} problem files")
+
+    problems = []
+    skipped = 0
+    for f in org_files:
+        p = parse_file(f)
+        if p:
+            problems.append(p)
+        else:
+            skipped += 1
+            print(f"  skipped: {f.name}")
+
+    print(f"Parsed: {len(problems)} problems, {skipped} skipped")
+
+    content = generate_cards(problems)
+
+    if dry_run:
+        print(f"\nWould write {len(problems)} cards to {OUTPUT}")
+        # Show first 3 cards as preview
+        preview = content.split("\n\n\n")[:3]
+        print("\n--- Preview ---")
+        print("\n\n".join(preview))
+    else:
+        OUTPUT.parent.mkdir(parents=True, exist_ok=True)
+        OUTPUT.write_text(content)
+        print(f"\nWrote {len(problems)} cards to {OUTPUT}")
+
+
+if __name__ == "__main__":
+    main()