#1752 - Check if Array Is Sorted and Rotated

Easy • View on LeetCode • View on GitHub

Problem Description

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.

Solution

/**
 * @param {number[]} nums
 * @return {boolean}
 */
var check = function(nums) {
  let count = 0;

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

  if (nums[nums.length - 1] > nums[0]) {
    count++;
  }

  return count < 2 ? true : false;
};