Initialize first width - First column of tSum array
for ( k = 1 ; k < n ; k ++ ) for ( j = 1 ; j < m ; j ++ ) tSum [ 0 ] [ j ] [ k ] = min ( tSum [ 0 ] [ j ] [ k - 1 ] , tSum [ 0 ] [ j - 1 ] [ k ] , INT_MAX ) + arr [ 0 ] [ j ] [ k ] ;