The?score?of an array is defined as the?product?of its sum and its length.

• For example, the score of?[1, 2, 3, 4, 5]?is?(1 + 2 + 3 + 4 + 5) * 5 = 75.

Given a positive integer array?nums?and an integer?k, return?the?number of non-empty subarrays?of?nums?whose score is?strictly less?than?k.

A?subarray?is a contiguous sequence of elements within an array.

?

Example 1:

Input: nums = [2,1,4,3,5], k = 10

Output: 6

Explanation:

The 6 subarrays having scores less than 10 are:?

- [2] with score 2 * 1 = 2.

- [1] with score 1 * 1 = 1.?

- [4] with score 4 * 1 = 4.?

- [3] with score 3 * 1 = 3.

- [5] with score 5 * 1 = 5.?

- [2,1] with score (2 + 1) * 2 = 6.?

Note that subarrays such as [1,4] and [4,3,5] are not considered because their scores are 10 and 36 respectively, while we need scores strictly less than 10.

Example 2:

Input: nums = [1,1,1], k = 5

Output: 5

Explanation:

Every subarray except [1,1,1] has a score less than 5.

[1,1,1] has a score (1 + 1 + 1) * 3 = 9,

which is greater than 5.?

Thus, there are 5 subarrays having scores less than 5.

?先放一個(gè)超時(shí)的代碼，

數(shù)據(jù)都沒問題，但是就是超時(shí)了。

然后就是這個(gè)雙指針的方法，就是能過，我挺奇怪的。。。時(shí)間復(fù)雜度應(yīng)該是一樣的啊。

Constraints:

• 1 <= nums.length <= 105

• 1 <= nums[i] <= 105

• 1 <= k <= 1015

Runtime:?5 ms, faster than?14.17%?of?Java?online submissions for?Count Subarrays With Score Less Than K.

Memory Usage:?52.7 MB, less than?56.25%?of?Java?online submissions for?Count Subarrays With Score Less Than K.