why don't you consider the points where three lines intersect and will create 6 equilateral triangles in a hexagon?

can you explain this "then multiplied that by 2^(nbtotal_white-k)"?

can you explain the aproach.i could not understand solution from editorial why cyclic shift work?

hey can you explain your approach? why you multiplied v[i] += dp1[j][i]*dp1[k-j-1][i];