Problem
The adapter pattern lets code that expects one interface work with objects that provide another. Here, a dashboard only understands degrees Celsius, but the sensors report in different units.
Each reading is a unit letter, a colon and a value:
C:<value>: already Celsius.F:<value>: Fahrenheit, converted with (F − 32) × 5 / 9.K:<value>: Kelvin, converted with K − 273.15.
Implement sensor_adapter(readings).
Input
readings: The raw sensor readings.
Output
Return every reading in Celsius, in order. Answers within 1e-6 are accepted.
Constraints
1 ≤ number of readings ≤ 1,000
−1,000 ≤ value ≤ 1,000
Examples
Input:
readings = ["C:21.5", "F:212", "K:273.15"]
Expected output:
expected = [21.5, 100.0, 0.0]Input:
std::vector<std::string> readings = {"C:21.5", "F:212", "K:273.15"};
Expected output:
std::vector<double> expected = {21.5, 100.0, 0.0};Input:
string[] readings = new string[] {"C:21.5", "F:212", "K:273.15"};
Expected output:
double[] expected = new double[] {21.5, 100.0, 0.0};Explanation
21.5 °C stays; 212 °F is (212 − 32) × 5 / 9 = 100 °C; 273.15 K is 0 °C.
Input:
readings = ["F:-40"]
Expected output:
expected = [-40.0]Input:
std::vector<std::string> readings = {"F:-40"};
Expected output:
std::vector<double> expected = {-40.0};Input:
string[] readings = new string[] {"F:-40"};
Expected output:
double[] expected = new double[] {-40.0};Explanation
−40 is the same in both scales: (−40 − 32) × 5 / 9 = −40.
How to approach it
Try on your own first, then open one hint at a time.
Hint 1
The letter before the colon tells you the unit.
Hint 2
Convert every reading to Celsius with its own formula.
Hint 3
Parse the number after the colon as a decimal, including negative values.
Expected complexity
O(number of readings) time, O(number of readings) extra space
References
This challenge is adapted for CodeUtility. Follow the statement and constraints above.