{
    "name": "task_medium_decoder_logic",
    "difficulty": "medium",
    "description": "Fix the logic error in the 2-to-4 decoder. One output equation uses the wrong input polarity.",
    "bug_type": "logic",
    "hint": "Check which output should be active for a=0, b=1.",
    "expected_sim_output": "a b | y3 y2 y1 y0\n-----------------\n0 0 |  0  0  0  1\n0 1 |  0  0  1  0\n1 0 |  0  1  0  0\n1 1 |  1  0  0  0"
}