Problem Statement |
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You have a device that measures temperature once a minute. Sadly, the temperature sensor of your device is not 100% reliable,
and sometimes it reports wildly inaccurate values.
You don't have the resources to buy a new device so you decide to fix the problem by writing software for your device that will throw away invalid measurements.
We consider a measurement invalid if:
- the value is less than -273, or
- each value that was measured within 2 minutes before and after this one differs from this value by more than 2
In other words, when deciding whether a measurement is valid, you usually consider the previous two, and the next two measurements.
You are given a int[] measuredValues that contains temperatures measured in the last few minutes.
The temperatures are given in chronological order, i.e., the i-th value is the temperature measured i minutes after the device was started.
Write a method that computes the average of the valid measurements. If no measurement is valid, return -300.0.
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Definition |
| | | Class: | MeasuringTemperature | | Method: | averageTemperature | | Parameters: | int[] | | Returns: | double | | Method signature: | double averageTemperature(int[] measuredValues) | | (be sure your method is public) |
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Notes |
| - | The returned value must be accurate to within a relative or absolute error of 1E-9. |
| - | The lowest possible temperature (in degrees Celsius) is -273.15. |
| - | It may seem weird that only integer temperatures are used in the input. This is only done to avoid rounding errors. |
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Constraints |
| - | measuredValues contains between 2 and 50 elements, inclusive. |
| - | Each element of measuredValues will be between -1000 and 1000, inclusive. |
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Examples |
| 0) | |
| | | Returns: 12.0 | | All measurements are valid. During this period of time it was getting warmer. The average temperature is (9+11+12+13+15)/5 = 12. |
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| 1) | |
| | | Returns: 0.16666666666666666 | | The fifth measurement is clearly invalid. The average of the valid ones is slightly positive. |
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| 2) | |
| | | Returns: 0.16666666666666666 | | This time, the fifth measurement is only slightly off, but still we consider it to be invalid. |
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| 3) | |
| | | Returns: -0.2857142857142857 | | All the measurements are valid. |
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| 4) | |
| | | Returns: 29.857142857142858 | | Again, all these measurements are valid. (Sadly, the sensor malfunctioned twice in a row. Our approach can't deal with this situation.) |
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| 5) | |
| | | Returns: 4.0 | | The last measurement is invalid. (The measurements made within 2 minutes from the last measurement gave results 6 and 7, and neither of these values is close enough to 10.) |
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| 6) | |
| | {-35, -34, -34, -34, -35, 72, -34, 52, -36, -35, -36, 52, -36, -35, 981, -33} |
| Returns: -34.75 | | It's freezing cold and the sensor is malfunctioning quite often, but luckily we can identify all the wrong measurements (72, 52, 52, and 981) as invalid. |
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| 7) | |
| | | Returns: -273.0 | | The third measurement gives a temperature lower than -273, and thus is considered to be invalid. |
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| 8) | |
| | | Returns: -300.0 | | No valid measurements here. |
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