Variable Window Size Template

variable_window()
{
    int start = 0, end = 0;
    while (end < n)
    {
        // Perform calculations or operations within the window

        /* Case 1: Expand the window
           If the window size is less than the desired value (k), increase the end index
        */
        if (end - start + 1 < k)
        {
            end++;
        }

        /* Case 2: Window of desired size
           If the window size is equal to the desired value (k), process the window and calculate the answer
        */
        else if (end - start + 1 == k)
        {
            // Perform the required calculations or operations to obtain the answer
            // Store the answer in a variable (ans)

            end++;
        }

        /* Case 3: Reduce the window size
           If the window size is greater than the desired value (k), adjust the window by moving the start index
        */
        else if (end - start + 1 > k)
        {
            while (end - start + 1 > k)
            {
                // Remove calculations or operations involving the element at the start index

                start++;
            }

            // Check if the window size becomes equal to the desired value (k) after adjustment
            if (end - start + 1 == k)
            {
                // Perform calculations or operations and store the answer if necessary
            }

            end++;
        }
    }

    // Return the final answer (ans)
}