Nomor 1

package nomor1;

public class Nomor1
{
    public static void main(String[] args)
    {
        int[][] arr = {{1,1,1,1}, {0,1,6,6}, {0,0,7,7}, {0,0,0,5}};
        int countZero = 0;
        int countRow = 0;

        //Print array
        for(int i=0;i<arr.length;i++)
        {
            for(int j=0;j<arr[0].length;j++)
            {
                System.out.print(arr[i][j] + " ");
            }

            System.out.println();
        }

        //Check if matrix is upper triangular matrix
        for(int i=0;i<arr.length;i++)
        {
            for(int j=0;j<arr[0].length;j++)
            {
                if(i == 0)
                {
                    if(arr[i][j] == 0)
                    {
                        countRow++;
                    }
                } else
                {
                    if(j < i-1)
                    {
                        if(arr[i][j] == 0)
                        {
                          countZero++;
                        } else
                        {
                            countRow++;
                        }
                    } else
                    {
                        if(arr[i][j] == 0)
                        {
                          countRow++;
                        }
                    }
                }
            }

            if(i > 0)
            {
                if(countZero == i)
                {
                    countRow++;
                }
            }

            countZero = 0;
        }

        if(countRow == arr.length-1)
        {
            System.out.println("Matrix segitiga atas");
        } else
        {
            System.out.println("Bukan matrix segitiga atas");
        }
    }
}