Sorting

input/code.cpp: In function 'int main()':
input/code.cpp:11:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%lld",&t);
  ~~~~~^~~~~~~~~~~
input/code.cpp:14:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%lld",&n);
   ~~~~~^~~~~~~~~~~
input/code.cpp:17:9: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
    scanf("%lld",a+i);
    ~~~~~^~~~~~~~~~~~

#include <bits/stdc++.h>

using namespace std;

long long n,a[100069],pst[100069];

int main()
{
	long long t,rr,i,ii,k,c,z;
	
	scanf("%lld",&t);
	for(rr=0;rr<t;rr++)
	{
		scanf("%lld",&n);
		for(i=1;i<=n;i++)
		{
			scanf("%lld",a+i);
			pst[a[i]]=i;
		}
		if(n<4)
		{
			for(i=1;i<=n;i++)
			{
				if(a[i]!=i)
				{
					break;
				}
			}
			z=i>n;
		}
		else if(n==4)
		{
			for(ii=0;ii<2;ii++)
			{
				for(i=1;i<=n;i++)
				{
					if(a[i]!=(i+ii*2-1)%n+1)
					{
						break;
					}
				}
				if(i>n)
				{
					break;
				}
			}
			z=ii<2;
		}
		else
		{
			c=0;
			for(i=1;i<=n;i++)
			{
				if(a[i]!=i)
				{
					c++;
					k=pst[i];
					swap(a[i],a[k]);
					swap(pst[a[i]],pst[a[k]]);
				}
			}
			z=c%2==0;
		}
		if(z)
		{
			printf("YES\n");
		}
		else
		{
			printf("NO\n");
		}
	}
}

Test 1

Group: 1, 2

Verdict: ACCEPTED

Test 2

Group: 2

Verdict: ACCEPTED

Test 3

Group: 1, 2

Verdict: ACCEPTED

Test 4

Group: 1, 2

Verdict: ACCEPTED