Larry's Array

Larry has been given a permutation of a sequence of natural numbers incrementing from 1 as an array. He must determine whether the array can be sorted using the following operation any number of times:

• Choose any 3 consecutive indices and rotate their elements in such a way that .

For example, if :

A		rotate 
[1,6,5,2,4,3]	[6,5,2]
[1,5,2,6,4,3]	[5,2,6]
[1,2,6,5,4,3]	[5,4,3]
[1,2,6,3,5,4]	[6,3,5]
[1,2,3,5,6,4]	[5,6,4]
[1,2,3,4,5,6]

YES

On a new line for each test case, print YES if A can be fully sorted. Otherwise, print NO.

Example:

Input: n = 3, A = {3, 1, 2}
Output: YES

Approach

C++

#include <bits/stdc++.h>
using namespace std;

string larrysArray(vector<int> A)
{
    int a = 0;
    for (int j = 0; j < A.size(); j++)
    {
        for (int k = j + 1; k < A.size(); k++)
        {
            if (A[j] > A[k])
                a += 1;
        }
    }
    if (a % 2 == 0)
        return "YES";
    else
        return "NO";
}

int main()
{

    int n = 3;
    vector<int> A = {3, 1, 2};

    cout << larrysArray(A) << "\n";
    return 0;
}