exec'D,E,Q=input();J=0;exec"F=lambda u,m,j,i:+(j[i]<=u<j[-~i])if m<1else(u-j[i])/(j[i+m]-j[i])*F(u,~-m,j,i)+(j[-~i+m]-u)/(j[-~i+m]-j[-~i])*F(u,~-m,j,-~i);print F(D,E,Q,J);J+=1;"*(~-len(Q)-E);print;'*5
.5,0,[0,.5,1] .5,1,[-1,0,1,2] .9,1,[-1,0,1,2,3] 1.1,1,[-1,0,1,2,3] 3.,3,[-1,0,1,2,3,8,10,12,15,20]