Sum of Subarray Ranges LeetCode

 You are given an integer array nums. The range of a subarray of nums is the difference between the largest and smallest element in the subarray.

Return the sum of all subarray ranges of nums.

A subarray is a contiguous non-empty sequence of elements within an array.

 

Example 1:

Input: nums = [1,2,3]

Output: 4

Explanation: The 6 subarrays of nums are the following:

[1], range = largest - smallest = 1 - 1 = 0 

[2], range = 2 - 2 = 0

[3], range = 3 - 3 = 0

[1,2], range = 2 - 1 = 1

[2,3], range = 3 - 2 = 1

[1,2,3], range = 3 - 1 = 2

So the sum of all ranges is 0 + 0 + 0 + 1 + 1 + 2 = 4.

Example 2:

Input: nums = [1,3,3]

Output: 4

Explanation: The 6 subarrays of nums are the following:

[1], range = largest - smallest = 1 - 1 = 0

[3], range = 3 - 3 = 0

[3], range = 3 - 3 = 0

[1,3], range = 3 - 1 = 2

[3,3], range = 3 - 3 = 0

[1,3,3], range = 3 - 1 = 2

So the sum of all ranges is 0 + 0 + 0 + 2 + 0 + 2 = 4.

Example 3:

Input: nums = [4,-2,-3,4,1]

Output: 59

Explanation: The sum of all subarray ranges of nums is 59.

class Solution {

    public long subArrayRanges(int[] nums) {

      long sum = 0;

        int n = nums.length;

        for (int i = 0; i < n; i++) {

            int minVal = nums[i], maxVal = nums[i];

            for (int j = i; j < n; j++) {

                minVal = Math.min(minVal, nums[j]);

                maxVal = Math.max(maxVal, nums[j]);

                sum += (maxVal - minVal);

            }

        }

        return sum;  

    }

}