public static double[] findAverages(int K, int[] arr) {

double[] result = new double[arr.length - K + 1];

int windowSum = 0;

int windowStart = 0;

for (int windowEnd = 0; windowEnd < arr.length; windowEnd++) {

windowSum += arr[windowEnd];

if (windowEnd >= K - 1) {

result[windowStart] = (double)windowSum / K; //calculate the average for the current window

windowSum -= arr[windowStart]; //subtract the element going out

windowStart += 1; //slide window ahead

}

}

return result;

}

public static void main(String[] args) {

double[] result = AverageOfSubarrayOfSizeK.findAverages(5, new int[] { 1, 3, 2, 6, -1, 4, 1, 8, 2 });

System.out.println("Averages of subarrays of size K: " + Arrays.toString(result));

}