{"id":"left-leaf-root-never-counted","text":"A single-node tree returns 0 from `sum_of_left_leaves` because the root is seeded with `is_left=False` — the root cannot be a \"left leaf\" regardless of its children.","truth_value":"IN","source":"entries/2026/06/06/sum-of-left-leaves-solution.md","source_url":"","source_hash":"","justifications":[],"dependents":[],"metadata":{},"created_at":"","updated_at":"","reviewed_at":"","verified_at":"","retracted_at":"","explanation":{"steps":[{"node":"left-leaf-root-never-counted","truth_value":"IN","reason":"premise"}]}}