Tricky Subarrays

Problem Preview

"### Problem You are given a permutation A of length N. There are Q queries. In each query, you are given L and R. Determine the number of subsequences B from the subarray A[L...R] such that |B| = max(B). |B| is the length of the array B. ### Input - N: Represents the length of the permutation A - A: Represents N space-separated integers denoting the permutation elements - Q: Represents the number of queries - Queries: Represents Q ranges L, R given in a 2D array ### Output For each test case, print Q space-separated integers answer to each query modulo (10^9+7) in a new line. ### Constraints - 1 <= N <= 10^5 - 1 <= Q <= 10^5 - 1 <= L <= R <= N - A is a permutation of length N, so all elements are unique ### Subtle Requirements - The problem requires counting subsequences where the length of the subsequence equals the maximum element in the subsequence. - The answer should be given modulo (10^9+7). ### Example 1 - N = 3 - A = [2,1,3] - Q = 1 - Queries = [[2,3]] The subarray from L = 2 to R = 3 is [1,3]. There is only one subsequence (1) that satisfies the given condition. ### Example 2 - N = 4 - A = [2,3,1,4] - Q = 2 - Queries = [[1,2],[2,3]] The subarray from L = 1 to R = 2 is [2,3]. No subsequence satisfies the given condition. The subarray from L = 2 to R = 3 is [3,1]. There is only one subsequence (1) that satisfies the given condition."