Check if array is sorted and rotated

Array

55.7% acceptance

Feb 25, 2026

4870

285

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], for all valid values of i.

Solution

Rust

Time O(n)

Space O(1)

LeetCode

solution.rs

impl Solution {
  pub fn check(nums: Vec<i32>) -> bool {
    let n = nums.len();
    let descents = (0..n).filter(|&i| nums[i] > nums[(i + 1) % n]).count();
    descents <= 1
  }
}