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1752. Check If Array Is Sorted and Rotated

EasyOpen on LeetCodeProblem statement

Problem Statement

1752. Check if Array Is Sorted and Rotated

Easy


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.

 

Constraints:

Java

Source file
class Solution {
    public boolean check(int[] nums) {
        boolean pivotFound = false;
        for (int i = 1; i < nums.length; i++) {
            if (nums[i] < nums[i - 1])
                if (pivotFound)
                    return false;
                else
                    pivotFound = true;
        }
        return nums[nums.length - 1] < nums[0] || !pivotFound;
    }
}