1752. Check if Array Is Sorted and Rotated.js

// Given an array nums, return true if the array was originally sorted in non-decreasing order, then rotated some number of positions (including zero). Otherwise, return false.

// There may be duplicates in the original array.

// Note: An array A rotated by x positions results in an array B of the same length such that A[i] == B[(i+x) % A.length], where % is the modulo operation.

// Example 1:

// Input: nums = [3,4,5,1,2]
// Output: true
// Explanation: [1,2,3,4,5] is the original sorted array.
// You can rotate the array by x = 3 positions to begin on the the element of value 3: [3,4,5,1,2].
// Example 2:

// Input: nums = [2,1,3,4]
// Output: false
// Explanation: There is no sorted array once rotated that can make nums.
// Example 3:

// Input: nums = [1,2,3]
// Output: true
// Explanation: [1,2,3] is the original sorted array.
// You can rotate the array by x = 0 positions (i.e. no rotation) to make nums.

const check = nums => {
	let occur = Number(nums.at(-1) > nums[0])

	for (let i = 0; i < nums.length; i++) {
		if (nums[i] > nums[i + 1]) occur++
	}

	return occur < 2
}