Package g2001_2100.s2090_k_radius_subarray_averages

Class Solution

  • public class Solution
extends Object
    2090 - K Radius Subarray Averages.

    Medium

    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

    • Constructor Detail

      • Solution

        public Solution()

    • Method Detail

      • getAverages

        public int[] getAverages​(int[] nums,
                         int k)