Count Increasing Triplets

Problem Statement

Count Increasing Triplets Problem Description Given an array of integers, return the number of strictly increasing subsequences of length 3. The result should be returned modulo 10 9 + 7. Note A subsequence is a sequence that can be derived from an array by deleting zero or more elements without changing the order of the remaining elements. Example 1 Input: n = 5, arr = [1, 2, 3, 4, 1] Output: 4 Explanation: The strictly increasing subsequences of length three are: [1, 2, 3] (from indices 0, 1, 2) [1, 2, 4] (from indices 0, 1, 3) [1, 3, 4] (from indices 0, 2, 3) [2, 3, 4] (from indices 1, 2, 3) There are 4 such subsequences. The answer is 4 modulo (10 9 + 7), which is 4.