寡头市场特征

def solve(market_features):
    required = ["少数厂商", "相互依存", "进入壁垒"]
    met = [f for f in market_features if f in required]
    is_oligopoly = len(met) >= 2
    return {"市场特征": market_features, "满足条件数": len(met), "是寡头市场": is_oligopoly}