/* For each (vi,vj) computes shortest path s_ij = |vi..vj|
* along edges, and actual distance d_ij = |vi-vj|.
*
/* For each (vi,vj) computes shortest path s_ij = |vi..vj|
* along edges, and actual distance d_ij = |vi-vj|.
*
//printf("layout %03x..%03x dist^2=%d s^2=%g d^2=%g "
//" cost+=%g\n", v1,v2, dist2,
//printf("layout %03x..%03x dist^2=%d s^2=%g d^2=%g "
//" cost+=%g\n", v1,v2, dist2,