rule redundancy checking is done in hwt, making it have better result on dup and even
(especially on dup). This enable hwt to choose better dim for bcut. But the computation
burden is also greatly increased. Optimize it in the future. For now, still need to
shorten the tree, which is 8 for 10000acl.

N[216<-0#9603]@1: #482
N[1083<-216#482]@2: #9
N[1808<-1083#9]@3: #8
N[2203<-1808#8]@4: #8
N[2355<-2203#8]@5: #7
N[2421<-2355#7]@6: #5
N[2439<-2421#5]@7: #2
size[8]: np=271, nc=1311
Trie nodes: 2440