Today I have done leetcode's February LeetCoding Challenge with cpp.

February LeetCoding Challenge 2

Description

Check if Array Is Sorted and Rotated

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:

• 1 <= nums.length <= 100
• 1 <= nums[i] <= 100

Solution

class Solution {
public:
  bool check(vector<int>& nums) {
    int r = 0;
    int cur = nums.front();
    for(auto n : nums) {
      if(cur > n) r += 1;
      cur = n;
    }
    return r == 0 || (r == 1 && nums.front() >= nums.back());
  }
};

// Accepted
// 109/109 cases passed (0 ms)
// Your runtime beats 100 % of cpp submissions
// Your memory usage beats 58.89 % of cpp submissions (11.2 MB)