You are given a 0-indexed array `nums` of `n` integers, and an integer `k`.

The k-radius average for a subarray of `nums` centered at some index `i` with the radius `k` is the average of all elements in `nums` between the indices `i - k` and `i + k` (inclusive). If there are less than `k` elements before or after the index `i`, then the k-radius average is `-1`.

Build and return an array `avgs` of length `n` where `avgs[i]` is the k-radius average for the subarray centered at index `i`.

The average of `x` elements is the sum of the `x` elements divided by `x`, using integer division. The integer division truncates toward zero, which means losing its fractional part.

- For example, the average of four elements `2`, `3`, `1`, and `5` is `(2 + 3 + 1 + 5) / 4 = 11 / 4 = 2.75`, which truncates to `2`.

Example 1:

    Input: nums = [7,4,3,9,1,8,5,2,6], k = 3
    Output: [-1,-1,-1,5,4,4,-1,-1,-1]
    Explanation:
    - avg[0], avg[1], and avg[2] are -1 because there are less than k elements before each index.
    - The sum of the subarray centered at index 3 with radius 3 is: 7 + 4 + 3 + 9 + 1 + 8 + 5 = 37.
      Using integer division, avg[3] = 37 / 7 = 5.
    - For the subarray centered at index 4, avg[4] = (4 + 3 + 9 + 1 + 8 + 5 + 2) / 7 = 4.
    - For the subarray centered at index 5, avg[5] = (3 + 9 + 1 + 8 + 5 + 2 + 6) / 7 = 4.
    - avg[6], avg[7], and avg[8] are -1 because there are less than k elements after each index.

Example 2:

    Input: nums = [100000], k = 0
    Output: [100000]
    Explanation:
    - The sum of the subarray centered at index 0 with radius 0 is: 100000.
      avg[0] = 100000 / 1 = 100000.

Example 3:

    Input: nums = [8], k = 100000
    Output: [-1]
    Explanation:
    - avg[0] is -1 because there are less than k elements before and after index 0.

Constraints:

- `n == nums.length`
- `1 <= n <= 105`
- `0 <= nums[i], k <= 105`