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Java-based LeetCode algorithm problem solutions, regularly updated
1630\. Arithmetic Subarrays
Medium
A sequence of numbers is called **arithmetic** if it consists of at least two elements, and the difference between every two consecutive elements is the same. More formally, a sequence `s` is arithmetic if and only if `s[i+1] - s[i] == s[1] - s[0]` for all valid `i`.
For example, these are **arithmetic** sequences:
1, 3, 5, 7, 9 7, 7, 7, 7 3, -1, -5, -9
The following sequence is not **arithmetic**:
1, 1, 2, 5, 7
You are given an array of `n` integers, `nums`, and two arrays of `m` integers each, `l` and `r`, representing the `m` range queries, where the ith
query is the range `[l[i], r[i]]`. All the arrays are **0-indexed**.
Return _a list of_ `boolean` _elements_ `answer`_, where_ `answer[i]` _is_ `true` _if the subarray_ `nums[l[i]], nums[l[i]+1], ... , nums[r[i]]` _can be **rearranged** to form an **arithmetic** sequence, and_ `false` _otherwise._
**Example 1:**
**Input:** nums = `[4,6,5,9,3,7]`, l = `[0,0,2]`, r = `[2,3,5]`
**Output:** `[true,false,true]`
**Explanation:**
In the 0th query, the subarray is [4,6,5].
This can be rearranged as [6,5,4], which is an arithmetic sequence.
In the 1st query, the subarray is [4,6,5,9]. This cannot be rearranged as an arithmetic sequence.
In the 2nd query, the subarray is `[5,9,3,7]. This` can be rearranged as `[3,5,7,9]`, which is an arithmetic sequence.
**Example 2:**
**Input:** nums = [-12,-9,-3,-12,-6,15,20,-25,-20,-15,-10], l = [0,1,6,4,8,7], r = [4,4,9,7,9,10]
**Output:** [false,true,false,false,true,true]
**Constraints:**
* `n == nums.length`
* `m == l.length`
* `m == r.length`
* `2 <= n <= 500`
* `1 <= m <= 500`
* `0 <= l[i] < r[i] < n`
* -105 <= nums[i] <= 105