[ { "solvable_probability": 0.8, "min_length": 2, "max_length": 15 }, { "solvable_probability": 0.7, "min_length": 3, "max_length": 8 }, { "solvable_probability": 0.5, "min_length": 1, "max_length": 10 }, { "solvable_probability": 1.0, "min_length": 5, "max_length": 20 } ]