Debug-Trie-Delete-V2

The model receives the prompt (and optional system message). The run uses scorer rubric_json_metrics with the JSON configuration below. Pass/fail and partial credit are determined entirely by that scorer against the model output; no human grading.

Return JSON only with keys diagnosis, fix, tests. A trie delete implementation removes all nodes along the deleted word's path without checking whether those nodes are shared prefix nodes of other words still in the trie; deleting 'car' also destroys 'card' and 'care'. Identify the prefix-sharing bug and fix it.

{
  "metrics": {
    "repro": {
      "checks": [
        {
          "contains": [
            "prefix"
          ]
        },
        {
          "contains": [
            "shared nodes"
          ]
        },
        {
          "contains": [
            "delete"
          ]
        },
        {
          "contains": [
            "trie"
          ]
        }
      ]
    },
    "hidden": {
      "checks": [
        {
          "contains": [
            "children"
          ]
        },
        {
          "contains": [
            "isEnd"
          ]
        },
        {
          "contains": [
            "child count"
          ]
        }
      ]
    },
    "diagnose": {
      "checks": [
        {
          "contains": [
            "shared prefix"
          ]
        },
        {
          "contains": [
            "premature deletion"
          ]
        },
        {
          "contains": [
            "other words"
          ]
        }
      ]
    }
  }
}