3700. Number of ZigZag Arrays II

You are given three integers n, l, and r. A ZigZag array of length n is defined as follows: - Each element lies in the range [l, r]. - No two adjacent elements are equal. - No three consecutive elements form a strictly increasing or strictly decreasing sequence. Return the total number of valid ZigZag arrays. Since the answer may be large, return it modulo 109 + 7. A sequence is said to be