Count Contiguous Subarrays With a Constant Difference

# Count Contiguous Subarrays With a Constant Difference Given an integer array `nums`, count its contiguous subarrays of length at least three whose adjacent differences are all equal. A difference may be positive, negative, or zero. Count subarrays by their start and end positions, so overlapping subarrays are counted separately. ### Function `int numberOfArithmeticSlices(vector<int>& nums)` ### Example 1 ```text Input: nums = [6,3,0,-3,7] Output: 3 ``` The qualifying subarrays are `[6,3,0]`, `[3,0,-3]`, and `[6,3,0,-3]`. Including the final `7` breaks the common difference. ### Example 2 ```text Input: nums = [5,5,5,5,5] Output: 6 ``` There are three length-three, two length-four, and one length-five qualifying subarrays. ### Constraints - `1 <= nums.length <= 5000`. - `-1000 <= nums[i] <= 1000`. ### Clarifications Do not count subsequences that skip elements. Length-one and length-two subarrays do not qualify, even though a two-element pair has one difference. Identical value sequences occurring at different positions count separately. ### What a Strong Answer Covers - Minimum length, contiguity, and overlapping subarrays. - Negative or zero differences and a break in an otherwise regular run. - Why every qualifying pair of endpoints is counted exactly once. - Correctness, count bounds, and resource usage.