python-example
ref: https://blog.csdn.net/m0_37966618/article/details/80374581"""
ID: ***
LANG: PYTHON3
TASK: wormhole
"""
fin = open ('wormhole.in', 'r')
fout = open ('wormhole.out', 'w')
N = int(fin.readline())
total_List = list()
def checkPairings(listGenrt,crd):
for i in range(len(crd)):#assign starting point
sPt = crd[i]
lG = list(listGenrt)
org = list(sPt)
nXt = []
num = 0
while(True):#checking solutions of this starting point
for tpl in listGenrt:
if sPt in tpl:
sPt = tpl[0 if tpl.index(sPt) == 1 else 1]
if tpl in lG:
lG.remove(tpl)
for x in crd:
if x[1] == sPt[1] and x != sPt and x[0] > sPt[0]:
if nXt==[] or (nXt!=[] and x[0] < nXt[0]):
nXt = x
if(nXt==[]):#can't find wh with the same Y value
break
sPt = list(nXt)
nXt = []
if sPt == org and len(lG)!=len(listGenrt):
num+=1
break
if num!=0:
total_List.append(listGenrt)
break
def createPairings(remaining):
if len(remaining)==0:
return
for x in range(1,len(remaining)):
if(x>1):
P2 = list(pairings)
#print("---{}".format(P2))
checkPairings(P2,crd)
del pairings[(len(P2)-int(len(remaining)/2)):len(P2)]
pairings.append((remaining[0], remaining[x]))
p = list(remaining)
p.pop(0)
p.pop(x-1)
createPairings(p)
if(x==len(remaining)-1 and len(pairings)==len(remaining)/2):
checkPairings(pairings,crd)
crd = list()
pairings = list()
for x in range(N):
c = list(map(int,fin.readline().split()))
crd.append(c)
#print(crd)
createPairings(crd)
fout.write("{}\n".format(str(len(total_List))))
fout.close(