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K Radius Subarray Averages

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

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.

K Radius Subarray Averages diagram

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 <= 10^5
  • 0 <= nums[i], k <= 10^5

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