In original problem 1175F - The Number of Subpermutations, it is required to count the number of subpermutations that consist number from 1 to r — l + 1, each appear exactly once

I managed to solve it using two pointers, expanding from position i whereas a[i] = 1

How do I count number of subpermutations, starting from x to x + r — l, for example : [1, 3, 2] and [2, 4, 3] also counts. Also, it would be great if someone can find the submission link for this problem. Thanks for helping me.