{
  "schema": "ml-prep/item@1",
  "item": {
    "id": "leetcode-20-valid-parentheses",
    "area": "programming",
    "topic": "data-structures",
    "origin": "external",
    "title": "Valid Parentheses",
    "skills": [
      "stack",
      "conditionals"
    ],
    "priority": "foundation",
    "difficulty": "easy",
    "estimated_minutes": 12,
    "prerequisites": [
      "strings"
    ],
    "source_id": "leetcode",
    "locator": {
      "document": "LeetCode Problem Set",
      "label": "Problem 20: Valid Parentheses"
    },
    "links": {
      "problem": "https://leetcode.com/problems/valid-parentheses/",
      "solution": "https://leetcode.com/problems/valid-parentheses/"
    },
    "selection_note": "A standard stack invariant problem with immediate judge feedback on malformed nesting and edge cases.",
    "answer_status": "official-interactive-feedback"
  }
}