价格下限分析

def solve(____):
    if floor_price <= equilibrium_price:
        return {"____": floor_price, "____": equilibrium_price, "____": "____"}
    a, b = demand_func
    c, d = supply_func
    qd = a - b * floor_price
    qs = c + d * floor_price
    surplus = qs - qd
    return {"____": floor_price, "____": qd, "____": qs, "____": surplus}