Skip to content

Optimize Subset Construction using hash #6

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
AnicoderAndy wants to merge 1 commit into
base: master
Choose a base branch
from
Open

Optimize Subset Construction using hash #6

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
15 changes: 8 additions & 7 deletions dfa/construction.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -19,6 +19,10 @@ def convert_to_dfa(nfa_start_node):
n_closure = closure(ns)
dfa = Dfa.nfas_to_dfa(n_closure)
dfa_list.append(dfa)

dfa_cache = {}
if n_closure is not None:
dfa_cache[frozenset(n_closure)] = dfa

dfa_index = 0
while dfa_index < len(dfa_list):
Expand All @@ -30,10 +34,11 @@ def convert_to_dfa(nfa_start_node):
nfa_closure = closure(nfa_move)
if nfa_closure is None:
continue
new_dfa = convert_completed(dfa_list, nfa_closure)
new_dfa = convert_completed(dfa_cache, nfa_closure)
if new_dfa is None:
new_dfa = Dfa.nfas_to_dfa(nfa_closure)
dfa_list.append(new_dfa)
dfa_cache[frozenset(nfa_closure)] = new_dfa
next_state = new_dfa.status_num
jump_table[dfa.status_num][c] = next_state
if new_dfa.accepted:
Expand All @@ -43,12 +48,8 @@ def convert_to_dfa(nfa_start_node):
return jump_table


def convert_completed(dfa_list, closure):
for dfa in dfa_list:
if dfa.nfa_sets == closure:
return dfa

return None
def convert_completed(dfa_cache, closure):
return dfa_cache.get(frozenset(closure))


def log_dfa(dfa_list):
Expand Down