Temperature Statistics

Input:

The input file is a stream of values read from sensors.

Each row represents a single reading from a specific sensor containing volume and temperature.

The input is a time series of values in columns:

< TimeStamp>,< Sensor>,< Volume>,< Temperature>

Definitions

• TimeStamp is value indicating the microseconds since midnight.
• Symbol is the 3 character unique identifier for a sensor
• Volume is the volume included in this reading
• Temperature is the average temperature during the period of the reading.

Safe Assumptions:

• TimeStamp - Always for the same day. Midnight is 0, and no rollover occurs. TimeStamp never decreases.
• Volume - volume is in liters and integer based, there will be no fractional measurements.
• Temperature - Temperature is measured in Kelvin, and will never be less than 0.

Even though input file is small, the program must be able to handle a dataset well beyond the space available on the computer.

Example: here is a row for a reading of 10L from sensor aaa at a temperature of 120 degrees K: 1234567,aaa,10,120

Problem:

Find the following on a per sensor basis:

• Maximum time gap
  (time gap = Amount of time that passes between consecutive readings of a sensor) if only 1 reading is in the file then the gap is 0.

• Total Volume
  (Sum of the volume for all readings from a sensor).

• Max Temperature
• Weighted Average Temperature. Average temperature per liter not per reading.

Report results in integers, no fractional values needed.

Example: the following readings
20L on aaa @ 18 degrees
5L of aaa @ 7 degrees
Weighted Average Temperature = ((20 * 18) + (5 * 7)) / (20 + 5) = 15 degrees

Output:

Your solution should produce a file called 'output.csv'.

file should be a comma separate file with this format:

< sensor>,< MaxTimeGap>,< Volume>,< WeightedAverageTemperature>,< MaxTemperature>

The output should be sorted by sensor ascending ('aaa' should be first).

Sample Input:

52924702,aaa,13,1136
52924702,aac,20,477
52925641,aab,31,907
52927350,aab,29,724
52927783,aac,21,638
52930489,aaa,18,1222
52931654,aaa,9,1077
52933453,aab,9,756

Sample Output:

aaa,5787,40,1161,1222
aab,6103,69,810,907
aac,3081,41,559,638