import java.util.Arrays;
import java.util.Scanner;

public class RaceResults
{
  public static void main(String[] args)
  {
    Scanner in = new Scanner(System.in);
    System.out.println("Enter count of runners:");
    int countOfRacers = in.nextInt(); // how many racers are in the race.

    double[] timesArray = new double[countOfRacers]; /// creates an array with the length of countOfRacers.
    double time;
    double averageTime;

    for (int i = 0; i < countOfRacers; i++) { /// this loop reads the input from the user and stores it in the arr Array.
      System.out.println("Please enter the time in seconds for runner " + (i + 1));
      time = in.nextDouble();
      timesArray[i] = time;
    }

    for (int i = 0; i < timesArray.length; i++) { /// this loop prints on the console the time of each racer.
      System.out.println("Runner number " + (i + 1) + " time is " + timesArray[i] + " seconds");
    }

    System.out.println(); // leaves space b/w different statistics.

    Arrays.sort(timesArray); //sorts from min to max value if int or double/alphabetical order if String Array!
    System.out.println("The fastest time is " + timesArray[0] + " seconds");
    System.out.println("The slowest time is " + (timesArray[timesArray.length - 1]) + " seconds");
    System.out.println();  // leaves space b/w different statistics.


    // long lay yo get average value ot the array
    //for (int i = 0; i < timesArray.length; i++) {
    //  averageTime += timesArray[i] / timesArray.length;
    //}

    // short way yo get the average value ot the array.
    averageTime = Arrays.stream(timesArray).sum(); // Using Arrays.stream() to convert arr to a stream and .sum()to sum
    System.out.println("Average time is: " + averageTime / timesArray.length + " seconds");
    System.out.println();

    //// formula for Standard Deviation

    double mean;
    double variance = 0;
    double standardDeviation;

    mean = Arrays.stream(timesArray).sum() / timesArray.length;
    System.out.println("Mean = " + mean);

    for (int i = 0; i < timesArray.length; i++) {
      variance += (Math.pow(Math.abs(timesArray[i] - mean), 2)) / (timesArray.length - 1);
    }
    System.out.println("Variance = " + variance);

    standardDeviation = Math.sqrt(variance);
    System.out.printf("Standard Deviation = " + "%.2f" ,standardDeviation);
    System.out.println(" SD");

  }
}