import java.io.*;
import java.util.Arrays;
 
class Ideone
{ 
	static int[] f(int a[][]){int i,d=0,k=0,l=0,n=a[0].length,m=a.length;int[]r=new int[m*n];if(a==null)return r;while(k<m&&l<n){for(i=l;i<n;++i)r[d++]=a[k][i];k++;for(i=k;i<m;++i)r[d++]=a[i][n-1];n--;if(k<m)for(i=n-1;i>=l;--i)r[d++]=a[m-1][i];m--;if(l<n)for(i=m-1;i>=k;--i)r[d++]=a[i][l];l++;}return r;}
 
	public static void main (String[] args)
	{ 
		int a[][] = {{}};
		int b[][] = {{1,2,3,4},{12,13,14,5},{11,16,15,6},{10,9,8,7}};
		int c[][] = {{1, 2, 3, 4, 5, 6},{7, 8, 9, 10, 11, 12},{13, 14, 15, 16, 17, 18}};
 
		System.out.println(Arrays.toString(f(a)));
		System.out.println(Arrays.toString(f(b)));
		System.out.println(Arrays.toString(f(c)));
	}
}

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