Check if Array is Sorted

Solved

Difficulty: Basic Accuracy: — Submissions: 0 Points: 1

Given an array arr[], tell whether it is sorted in non-decreasing order, meaning every element is greater than or equal to the one before it. Return true if it is, otherwise false.

Examples:

Input: arr[] = [10, 20, 30, 40, 50]

Output: true

Explanation: Each element is at least as large as the previous one.

Input: arr[] = [90, 80, 100, 70]

Output: false

Explanation: 80 comes after 90, so the order is broken.

Constraints:

1 ≤ arr.size() ≤ 10^5
-10^9 ≤ arr[i] ≤ 10^9

Expected Complexities

Time Complexity: O(n) Auxiliary Space: O(1)

Company Tags

Accenture

Topic Tags

Arrays Basic

Compare each element with its neighbour on the left. The moment you find one that is smaller, the answer is false; if you reach the end without that happening, the array is sorted. Arrays of length one are trivially sorted.

class Solution {
    isSorted(arr) {
        for (let i = 1; i < arr.length; i++) {
            if (arr[i] < arr[i - 1]) return false;
        }
        return true;
    }
}