Design Patterns: Structural · Coding problem

Plug Two Legacy Sensors Into One Interface

A free coding problem from the Adapter Pattern skill. Read it here, then solve it in the app in Java or Python.

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  • Easy
  • Coding problem
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  • Java and Python

The problem

The app reads temperatures through one interface, TemperatureSensor.celsius(). Two devices you can't change report temperatures their own way:

  • LegacyFahrenheitSensor.readTenthsOfFahrenheit() - tenths of a degree Fahrenheit (986 means 98.6 °F)
  • KelvinProbe.readMilliKelvin() - millikelvin (293150 means 293.15 K)

Complete the two adapters so both devices work as a TemperatureSensor:

  • FahrenheitSensorAdapter.celsius() - C = (F - 32) × 5 / 9
  • KelvinProbeAdapter.celsius() - C = K - 273.15

Notice that Solution and its average() never know which device they're talking to - that's what the adapters buy you.

In Python: the devices' methods are read_tenths_of_fahrenheit() and read_milli_kelvin(), and TemperatureSensor is an abstract base class.

Input: a count q, then q readings F <tenths> or K <millikelvin>. Output: each reading in Celsius to 1 decimal, then the average of all readings.

Example

Input:
3
F 986
K 293150
F 320

Output:
37.0 C
20.0 C
0.0 C
average 19.0 C

Constraints

  • 1 <= q <= 1000
  • Readings are between -100 °C and 200 °C.

How it's graded

  • Run checks your code against the examples. Submit also runs hidden tests, and you see pass or fail for them, never their inputs.
  • Stuck? Hints come in four steps, from a nudge to a code skeleton, each costing part of the points.
  • Once you pass, you see the approaches from brute force to optimal, and where your solution lands among them.

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