Package g0801_0900.s0891_sum_of_subsequence_widths

Class Solution

  • public class Solution
extends Object
    891 - Sum of Subsequence Widths.

    Hard

    The width of a sequence is the difference between the maximum and minimum elements in the sequence.

    Given an array of integers nums, return the sum of the widths of all the non-empty subsequences of nums. Since the answer may be very large, return it modulo 109 + 7.

    A subsequence is a sequence that can be derived from an array by deleting some or no elements without changing the order of the remaining elements. For example, [3,6,2,7] is a subsequence of the array [0,3,1,6,2,2,7].

    Example 1:

    Input: nums = [2,1,3]

    Output: 6

    Explanation:

    The subsequences are [1], [2], [3], [2,1], [2,3], [1,3], [2,1,3].

    The corresponding widths are 0, 0, 0, 1, 1, 2, 2.

    The sum of these widths is 6.

    Example 2:

    Input: nums = [2]

    Output: 0

    Constraints:

    • 1 <= nums.length <= 105
    • 1 <= nums[i] <= 105

    • Constructor Detail

      • Solution

        public Solution()

    • Method Detail

      • sumSubseqWidths

        public int sumSubseqWidths​(int[] nums)