Python 3370
Conseguí que esto fuera lo más funcional posible, e incluso obtuve alternancia para trabajar (¡con la verificación correcta de doble conteo!). Hasta donde yo sé, esto funciona para todo, excepto para las búsquedas (porque eso sería una locura).
Para cualquiera que escriba su propia solución, siéntase libre de usar / mejorar mis métodos tanto como desee.
Código:
R=range;L=len;E=enumerate;I=int;F="Infinity";S=sum;H=chr;D=ord;J=lambda l:''.join(l);U=lambda s:J([H(i)if H(i) not in s else''for i in R(1,128)]);s=' \n\t';c=J((H(i)if H(i)not in s else'')for i in R(1,32));d,l,u=[J(H(i)for i in R(*n))for n in [[48,59],[97,123],[65,91]]];p='`~!@#$%^&*()-_=+[{]}\\|;:\'",<.>/?';Y={'\\s':s,'\\S':c+s+p+u+l+d,'\\d':d,'\\D':U(d),'\\w':u+l+'_','\\W':U(u+l+'_'),'[:alnum:]':u+l+d,'[:alpha:]':u+l,'[:ascii:]':U(''),'[:blank:]':' \t','[:cntrl:]':c,'[:digit:]':d,'[:graph:]':p+d+l+u,'[:lower:]':l,'[:print:]':p+d+l+u+s,'[:punct:]':p,'[:space:]':s,'[:upper:]':u,'[:word:]':l+u+'_','[:xdigit:]':d+'ABCDEF'};C=lambda l,n:[d+[l[i]]for i in R(L(l))for d in C(l[i+1:],n-1)]if n>0 else[[]];O=lambda x:S([all((c in s)for s in [(e[1]if any(e[1] not in Y for e in x)else Y[e[1]])if e[0]=='e'else(e[1]if e[0]=='t'else((Y[e[1]]if e[1]in Y else B(e[1]))if e[0]=='['else''))for e in x])for c in Y['[:ascii:]']])
def X(r):
x=[];l=0;c=''
for h in r:
l+=I(h in'([')-I(h in')]')
if l<1 and'|'==h:x+=[c];c=''
else:c+=h
x+=[c]
if L(x)>1:
o=0;m=[];u=[]
for e in x:
p,b=X(e)
if p==F:return F,[]
o+=p;m+=[('(',b)];u+=[b]
return o-S([(-1)**(i%2)*T(s) for i in R(2,L(u)+1)for s in C(u,i)]),[('|',m)]
u=[];o=[];m=[];w=1
while r!='':
h=r[0];z=0
if h in'([{':
l=1;i=1
while l>0:k=r[i];l+=(k==h)-(k=={'(':')','[':']','{':'}'}[h]);i+=1
u+=[(h,r[1:i-1])];z=i
elif h=='\\':u+=[('e','\\'+eval("'\\%s'"%r[1]))]if r[1]in'nt'else[('e','\\'+r[1])];z=2
elif h in ['*','+','?']:u+=[('{',h)];z=1
elif h in'^$':return 0
elif h=='.':u+=[('[','[:ascii:]')];z=1
else:u+=[('t',h)];z=1
r=r[z:]
for t,g in u:
if t=='(':p,b=X(g);o+=[p];m+=[('(',b)]
elif t=='e':o+=[L(Y[g])]if g in Y else[1]
elif t=='[':o+=[N(g)]
elif t=='{':
n=o[-1]
try:o[-1]=S([n**r for r in Q(g)])
except:return F,[]
elif t=='t':o+=[1]
if t!='(':m+=[(t,g)]
for c in o:
if c==F:return F,[]
w*=c
return w,m
def N(s):
if s in Y:return L(Y[s])
if(s[0],s[-1])==('[',']'):return 1
n=(s[0]=='^');a=0
if n:s=s[1:]
while s!='':
if L(s)>=3 and s[1]=='-':a+=D(s[2])-D(s[0])+1;s=s[3:];continue
a+=1;s=s[1:]
return 256*n+(-1)**n*a
def Q(s):
if s=='?':return[0,1]
if s[0]in'*+':return None
if ','in s:
l,h=s.split(',')
return None if h==''else R(I(l),I(h)+1)
return[I(s)]
def B(s):
n=(s[0]=='^')
if n:s=s[1:]
a='';w=''
while s!='':
h=s[0]
if 3<=L(s)and'-'==s[1]:
for i in R(D(s[0]),D(s[2])+1):a+=H(i)
s=s[3:];continue
a+=h;s=s[1:]
return J([c*(c not in a)for c in Y['[:ascii:]']])if n else a
def T(x):
if all(e==[] for e in x):return 1
for i,e in E(x):
if L(e)>=2 and e[1][0]=='{':return S([T([[e[0]]*n+e[2:]]+x[:i]+x[i+1:])for n in Q(e[1][1])])
if L(e)>=1:
if e[0][0] == '(':return T([e[0][1]+e[1:]]+x[:i]+x[i+1:])
if e[0][0]== '|':
t=S(T([[s]+e[1:]]+x[:i]+x[i+1:])for s in e[0][1])
u=[[s]for s in e[0][1]]
return t-S((-1)**(j%2)*T(b)for j in R(2,L(u)+1)for b in C(u,j))
if any(e==[]for e in x):return 0
return O([e[0]for e in x])*T([e[1:]for e in x])
r=raw_input();e=[];l=0;c=''
for h in r:
l+=I(h in'([')-I(h in')]')
if l<1 and'|'==h:e+=[c];c=''
else:c+=h
e+=[c];o=[];x=[]
for f in e:
if '^'!=f[0]or'$'!=f[-1]:print F;quit()
n,m=X(f[1:-1])
if n==F:print F;quit()
o+=[n];x+=[m]
print S(o)-S([(-1)**(i%2)*T(s) for i in R(2,L(x)+1)for s in C(x,i)])
Sin golf:
controlchars = ''
for i in range(1,32):
if chr(i) not in '\t\n':
controlchars += chr(i)
CLASSES={
'\\s':' \t\n',
'\\S':controlchars+'!"#$%&\'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_`abcdefghijklmnopqrstuvwxyz{|}~',
'\\d':'0123456789',
'\\D':controlchars+'\n\t !"#$%&\'()*+,-./:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_`abcdefghijklmnopqrstuvwxyz{|}~',
'\\w':'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789_',
'\\W':controlchars+'\n\t !"#$%&\'()*+,-./:;<=>?@[\\]^`{|}~',
'[:alnum:]':'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789',
'[:alpha:]':'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ',
'[:ascii:]':controlchars+'\n\t !"#$%&\'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_`abcdefghijklmnopqrstuvwxyz{|}~',
'[:blank:]':' \t',
'[:cntrl:]':controlchars,
'[:digit:]':'0123456789',
'[:graph:]':'!"#$%&\'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_`abcdefghijklmnopqrstuvwxyz{|}~',
'[:lower:]':'abcdefghijklmnopqrstuvwxyz',
'[:print:]':'\n\t !"#$%&\'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_`abcdefghijklmnopqrstuvwxyz{|}~',
'[:punct:]':'`~!@#$%^&*()-_=+[{]}\\|;:\'",<.>/?',
'[:space:]':' \t\n',
'[:upper:]':'ABCDEFGHIJKLMNOPQRSTUVWXYZ',
'[:word:]':'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789_',
'[:xdigit:]':'0123456789ABCDEF'
}
DELIMIT = {
'(':')',
')':'(',
'[':']',
']':'[',
'{':'}',
'}':'{'
}
def combos(lst,num):
if num == 0:
return [[]]
combs = []
for i in range(len(lst)):
for c in combos(lst[i+1:],num-1):
combs.append([lst[i]]+c)
return combs
def count_regex(regex):
exprs = []
level = 0
current = ''
for char in regex:
if char in '([':
level += 1
if char in ')]':
level -= 1
if char == '|' and level == 0:
exprs.append(current)
current = ''
else:
current += char
exprs.append(current)
comps = []
expanded = []
for e in exprs:
if (e[0] != '^' or e[-1] != '$'):
return 'Infinity'
num,member = count_expr(e[1:-1])
if num == 'Infinity':
return 'Infinity'
comps.append(num)
expanded.append(member)
total = sum(comps)
for i in range(2,len(expanded)+1):
for subset in combos(expanded,i):
if i % 2 == 0:
total -= count_doubles(subset)
else:
total += count_doubles(subset)
return total
def count_expr(expr):
exprs = []
level = 0
current = ''
for char in expr:
if char in '([':
level += 1
if char in ')]':
level -= 1
if char == '|' and level == 0:
exprs.append(current)
current = ''
else:
current += char
exprs.append(current)
if len(exprs) != 1:
comps = 0
members = []
sub = []
for e in exprs:
comp,memb = count_expr(e)
if comp == 'Infinity':
return 'Infinity',[]
comps += comp
members.append(('(',memb))
sub.append(memb)
for i in range(2,len(sub)+1):
for subset in combos(sub,i):
if i % 2 == 0:
comps -= count_doubles(subset)
else:
comps += count_doubles(subset)
return comps,[('|',members)]
sub = []
while expr != '':
char = expr[0]
if char in ['(','[','{']:
level = 1
i = 1
while level > 0:
nchar = expr[i]
if nchar == char: level += 1
if nchar == DELIMIT[char]: level -= 1
i += 1
sub.append((char,expr[1:i-1]))
expr = expr[i:]
elif char == '\\':
if expr[1] == 'n':
sub.append(('e','\\'+'\n'))
expr = expr[2:]
elif expr[1] == 't':
sub.append(('e','\\'+'\t'))
expr = expr[2:]
else:
sub.append(('e','\\'+expr[1]))
expr = expr[2:]
elif char in ['*','+','?']:
sub.append(('{',char))
expr = expr[1:]
else:
if char in '^$':
return 0
if char == '.':
sub.append(('[','[:ascii:]'))
expr = expr[1:]
else:
sub.append(('t',char))
expr = expr[1:]
components = []
members = []
for t,string in sub:
if t == '(':
comp,memb = count_expr(string)
components.append(comp)
members.append(('(',memb))
elif t == 'e':
if string in CLASSES:
components.append(len(CLASSES[string]))
else:
components.append(1)
elif t == '[':
components.append(count_class(string))
elif t == '{':
num = components[-1]
try:
components[-1] = sum([num**r for r in count_quantifier(string)])
except TypeError:
return 'Infinity',[]
elif t == 't':
components.append(1)
if t != '(':
members.append((t,string))
total = 1
for c in components:
if c == 'Infinity':
return 'Infinity',[]
total *= c
return total,members
def count_class(string):
if string in CLASSES:
return len(CLASSES[string])
if string[0] == '[' and string[-1] == ']':
return 1
negate = (string[0] == '^')
if negate: string = string[1:]
avail_count = 0
while string != '':
char = string[0]
if len(string) >= 3:
if string[1] == '-':
first,last = string[0],string[2]
avail_count += ord(last)-ord(first)+1
string = string[3:]
continue
avail_count += 1
string = string[1:]
if negate:
return 256-avail-count
return avail_count
def count_quantifier(string):
if string == '?':
return [0,1]
if string[0] in '*+':
return None
if ',' in string:
low,high = string.split(',')
if high == '':
return None
return range(int(low),int(high)+1)
return [int(string)]
def bracket_string(string):
negate = (string[0] == '^')
if negate: string = string[1:]
avail = ''
while string != '':
char = string[0]
if len(string) >= 3:
if string[1] == '-':
first,last = string[0],string[2]
for i in range(ord(first),ord(last)+1):
avail += chr(i)
string = string[3:]
continue
avail += char
string = string[1:]
if negate:
new = ''
for c in CLASSES['[:ascii:]']:
if c not in avail:
new += c
return new
return avail
def overlap(es):
chars=['' for i in range(len(es))]
for i,e in enumerate(es):
if e[0] == 'e':
if any(e[1] not in CLASSES for e in es):
chars[i] = e[1]
else:
chars[i] = CLASSES[e[1]]
for i,e in enumerate(es):
if e[0] == 't':
chars[i] = e[1]
for i,e in enumerate(es):
if e[0] == '[':
if e[1] in CLASSES:
chars[i] = CLASSES[e[1]]
else:
chars[i] = bracket_string(e[1])
total = 0
for c in CLASSES['[:ascii:]']:
has = True
for chs in chars:
if c not in chs:
has = False
break
if has:
total += 1
return total
def count_doubles(exprs):
if all(e==[] for e in exprs):
return 1
for i,expr in enumerate(exprs):
if len(expr) >= 2 and expr[1][0] == '{':
rng = count_quantifier(expr[1][1])
total = 0
for n in rng:
total += count_doubles([ [expr[0]]*n+expr[2:] ] + exprs[:i] + exprs[i+1:])
return total
for i,expr in enumerate(exprs):
if len(expr) >= 1 and expr[0][0] == '(':
return count_doubles([ expr[0][1]+expr[1:] ] + exprs[:i] + exprs[i+1:] )
if any(e==[] for e in exprs):
return 0
for i,expr in enumerate(exprs):
if expr[0][0] == '|':
total = 0
subs = []
for sub_expr in expr[0][1]:
subs.append([sub_expr])
total += count_doubles([ [sub_expr]+expr[1:] ] + exprs[:i] + exprs[i+1:])
for j in range(2,len(subs)+1):
for subset in combos(subs,j):
if j % 2 == 0:
total -= count_doubles(subset)
else:
total += count_doubles(subset)
return total
over = overlap([e[0] for e in exprs])
if over == 0:
return 0
return over * count_doubles([e[1:] for e in exprs])
reg = raw_input('Regex: ')
print count_regex(reg)
Aquí hay algunos casos de prueba relevantes que he confirmado:
Regex: ^[A-Za-z0-9]{8}$
218340105584896
Regex: ^([a-b]*)$
Infinity
Regex: ^([0-9]|[a-e])([a-e]|[A-E])$|^[a-f]{2}$
161
Regex: ^[a-z]{2}$|^[0-9]?[a-z]{2,3}$|^a[a-z]?$
200773
Regex: ^([a-z]|[a-e]|[A-E]|[3-4]|[D-G])$
35
Regex: ^\(.)\(.)\2\1$
16129*
Regex: ^(a)\1?$
2
Regex: ^[[:space:]]$|^\t$
3
* Esto es realmente diferente en golfistas y no golfistas debido a una diferencia de un carácter en lo que se define como ascii válido. Creo que el golf es el más correcto.
Para confirmar su precisión, se podrían realizar más pruebas, por favor avíseme de cualquier error (sinceramente, no me sorprendería si hubiera bastantes).
^[A-Za-z0-9]{8}$? De lo contrario, la respuesta seríainfinity.