# 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

```java
```