import random
def FLIBgen():
   size = random.randint(2,26)
   count = 0
   FLIB = ""
   while count < size:
      FLIB = FLIB +(str(random.randint(0,1)) +chr(random.randint(65,65+size-1))+
      str(random.randint(0,1)) +chr(random.randint(65,65+size-1)) )
      count += 1
   return FLIB

def execution(flib,inputval):
   state = "A"
   outputval = ""
   count = 0
   while count < len(inputval):
      outputval =outputval +flib[(ord(state) -65) *4 +2*int(inputval[count])]
      state = flib[(ord(state) -65) *4 +2*int(inputval[count]) +1]
      count += 1
   return outputval

def mutation(flib):
   index = random.randint(0,len(flib)-1)
   if index&1 == 1:
      statenum = int(len(flib)/4)
      state = random.randint(0,statenum-1)
      flib = flib[:index] +chr(state+65) +flib[index+1:]
   else:
      state = str(random.randint(0,1))
      flib = flib[:index] +state +flib[index+1:]
   return flib

def crossover(flib1, flib2):
   #this could be better; currently appends two flibs, random length
   size1 = len(flib1)
   size2 = len(flib2)
   crossize1 = random.randint(0,size1-1)
   crosspos1 = random.randint(0,size1-crossize1-1)   
   crossize2 = random.randint(0,size2-1)
   crosspos2 = random.randint(0,size2-crossize2-1)
   newflib = flib1[crosspos1:crosspos1+crossize1]+flib2[crosspos2:crosspos2+crossize2]
   return newflib
   
def score(inputval,outputval):
   value1 = int(inputval,2)
   value2 = int(outputval,2)>>1
   size = len(inputval)
   result = bin(value1^value2^(1<<size)).count('0')-1
   return result/size