Arithmetic Subarrays
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, 97, 7, 7, 73, -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 i^th 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]In the 0th query, [4,6,5] can be rearranged as [6,5,4], the 1st query [4,6,5,9] cannot form an arithmetic sequence, and the 2nd query [5,9,3,7] can be rearranged as [3,5,7,9].
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]The queried subarrays can be rearranged into arithmetic sequences exactly for the 2nd, 5th, and 6th queries, producing the shown boolean results.
Constraints
- n == nums.length
- m == l.length
- m == r.length
- 2 <= n <= 500
- 1 <= m <= 500
- 0 <= l[i] < r[i] < n
- -10^5 <= nums[i] <= 10^5