ll@(x,y)[3],L[4]{1,-1,0,0},U[4]{0,0,1,-1};wt(max[i,0,64](abs((x[2]+L[i>>4]-*x-L[i&3])*(y[1]+U[i/4&3]-*y-U[i&3])-(x[1]+L[i/4&3]-*x-L[i&3])*(y[2]+U[i>>4]-*y-U[i&3]))/2.0));