{"id":"prev-zero-sentinel","text":"In `count_binary_substrings`, `prev` starts at 0 so the first group boundary contributes zero substrings via `min(0, curr)`, correctly handling the absence of a preceding group.","truth_value":"IN","source":"entries/2026/06/06/count-binary-substrings-solution.md","source_url":"","source_hash":"","justifications":[],"dependents":["sentinel-initialization-encodes-boundary-conditions"],"metadata":{},"created_at":"","updated_at":"","reviewed_at":"","verified_at":"","retracted_at":"","explanation":{"steps":[{"node":"prev-zero-sentinel","truth_value":"IN","reason":"premise"}]}}