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Check if array is sorted

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Problem statement

You are given an array ‘A’ of length ‘N’ , determine whether the array is sorted in non-decreasing order or not.

Example:

Input:
A = [1, 3, 6, 10]
Output:
True
Explanation: Since array ‘A’ is sorted, therefore output is ‘True’.

Detailed explanation ( Input/output format, Notes, Images )

Input Format:

The first line of the input contains an integer ‘N’.
The next line will contain ‘N’ space-separated integers.

Output Format:-

The output contains a string 'True' or 'False'.

Note:-

You don’t need to print anything. Just implement the given function.

Sample Input 1:

5
10 20 30 20 40

Sample Output 1:

False

Explanation Of Sample Input 1:

A = [10, 20, 30, 20, 40]
Since array ‘A’ is not sorted, therefore output is ‘False’.

Sample Input 2:

1
1100

Sample Output 2:

True

Constraints:

1 <= N  <= 10^5
1 <= A[i] <= 10^9

Hint 1

In a non-decreasing array, adjacent elements are increasing.

Approaches (1)

Approach 1

Iterative Method

Approach:

Iterate over the array and check if ‘A[i-1]’ <= ‘A[i]’, for all ‘i’ from 1 to ‘N’-1. (0-based indexing)
If the above condition is satisfied, then return true.
Else, return false.

Algorithm:

For ‘i’ from 1 to ‘N’-1:
- If ‘A[i-1]’ > ‘A[i]’:
  - Return false
Return true.

Time Complexity

O( N ), Where ‘N’ is the array ‘A’ length.

Iterating over an array of length ‘N’ takes O(N) complexity. Hence, the overall time complexity will be O( N ).

Space Complexity

O( 1 ).

We are taking O( 1 ) extra space for variables. Hence, the overall space complexity will be O( 1 ).

(100% EXP penalty)

Check if array is sorted

shivam malviya

Interview problems

Very simple in C++ (Check arraySortedOrNot)

bool arraySortedOrNot(vector<int>&A, int N) {

if(is_sorted(A.begin(),A.end())==true) return true;

return false;

}

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keerthi

Interview problems

beginner friendly java solution

public class Solution {

public static boolean arraySortedOrNot(int []A, int N) {

for(int i=1;i<N;i++)

if(A[i-1]>A[i])

return false;

return true;

}

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Yogesh Harichandra Bhat

Interview problems

Java | 2 Liner | O(n)

Please upvote if its helpful !

public class Solution {
    public static boolean arraySortedOrNot(int []A, int N) {
        for(int i = 1; i<N;i++) if(A[i-1]>A[i]) return false;
        return true;
    }
}

java

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TIPPANI KAVYA SRI

Interview problems

python

n=len(a)

if(n==1):

return True

for i in range(1,n):

if(a[i]<a[i-1]):

return False

return True

pass

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Bhavya Oberai

Interview problems

Runtime errror

C++

bool arraySortedOrNot(vector<int>&A, int N) {

if (N <= 1) return true;

if (A[N - 2] > A[N - 1]) return false;

return arraySortedOrNot(A, N - 1);

}

JAVA

public class Solution {

public static boolean arraySortedOrNot(int []A, int N) {

if (N <= 1) return true;

if (A[N - 2] > A[N - 1]) return false;

return arraySortedOrNot(A, N - 1);

}

CPP code is working fine but the same code in java is giving runtime error at 11/12th test case. what is the issue ?

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