Binary search

buf is the read block, k is the k-mer length, p = 12, len is the read length, seq is the read**/

just for mimatch edges

note: to use this function, don't renew unitig graph!!!!!!!!!

remove asymmetric arcs: u->v is present, but v'->u' not

hard remove arcs marked as "del"

in a resolved bubble, mark unused vertices and arcs as "reduced"

in a resolved bubble, mark unused vertices and arcs as "reduced"

pop bubbles