Frequency of each element of an array considering all contiguos subarrays

Question

Consider an array A = [5,1,7,2,3]

All contiguos subarrays = { [5], [1], [7], [2], [3], [5,1], [1,7], [7,2], [2,3], [5,1,7], [1,7,2], [7,2,3], [5,1,7,2], [1,7,2,3],

Answer 1

I doubt your code runs in O(n^2). Anyways, one way to solve this in a more efficient way would be to map each number to the number of items to the left/right which are smaller than the given item. For example:

input = [2 , 3 , 1 , 5 , 4 , 8 , 0]
for number n = 5
leftctsmaller(n) = 3
rightctsmaller(n) = 1

This map will require O(n^2) to generate. The rest is straightforward. Given the space to the left and to the right, we can easily determine the number of subarrays that only contains smaller numbers than n, except for n itself.