Sum of all good subarrays with adjacent difference ±1

Problem: Sum of all “good subarrays” where adjacent difference is ±1 Given an integer array nums of length n. A subarray is defined as good if and only if the absolute difference between every pair of adjacent elements in the subarray is exactly 1. That is, for all l < i ≤ r: |nums[i] - nums[i-1]| = 1 Compute the total sum of elements over all good subarrays (sum each good subarray, then sum over all such subarrays). Input (stdin) Line 1: integer n Line 2: n integers representing nums Output (stdout) One integer: the total sum over all good subarrays Constraints 1 ≤ n ≤ 2 * 10^5 -10^9 ≤ nums[i] ≤ 10^9 Required time complexity: O(n) Example Input: 5 3 5 6 7 6 Output: 69 Explanation: Good subarrays include all singletons and those with adjacent diff ±1, e.g. [5,6], [6,7], [7,6], [5,6,7]. Example Input 5 3 5 6 7 6 Output 69