0413. Arithmetic Slices

https://leetcode.com/problems/arithmetic-slices

Description

An integer array is called arithmetic if it consists of at least three elements and if the difference between any two consecutive elements is the same.

• For example, [1,3,5,7,9], [7,7,7,7], and [3,-1,-5,-9] are arithmetic sequences.

Given an integer array nums, return the number of arithmetic subarrays of nums.

A subarray is a contiguous subsequence of the array.

Example 1:

**Input:** nums = [1,2,3,4]
**Output:** 3
**Explanation:** We have 3 arithmetic slices in nums: [1, 2, 3], [2, 3, 4] and [1,2,3,4] itself.

Example 2:

**Input:** nums = [1]
**Output:** 0

Constraints:

• 1 <= nums.length <= 5000

• -1000 <= nums[i] <= 1000

ac