Adding the element of row 1 to both the elements of row 2 to reduce a step from the loop
if ( n > 1 ) tri [ 1 ] [ 1 ] = tri [ 1 ] [ 1 ] + tri [ 0 ] [ 0 ] ; tri [ 1 ] [ 0 ] = tri [ 1 ] [ 0 ] + tri [ 0 ] [ 0 ] ;