Which code has best runtime and why?(the one commented or the other one)

Question

# for key, value in dict.items():
            #     if value >= long:
            #         long = value
            #         long_name = key
            #     if value < short:
            #         short = value
            #         short_name = key
        long = max(dict.values())
        long_name = max(dict, key=dict.get)
        short = min(dict.values())
        short_name = min(dict, key=dict.get)