Problem 51: PRime Families

gistfile1.txt

# set up prime sieve to n- we'll need up to 999999 here, since we're investigating 6 figure combos
total = 0
n=1000000
myPrimes = [True]*(n+1)
mySum = [0]*(n+1)
last = 0
for i in range (2,n):
	if myPrimes[i] == True:
		j = 2*i
		while j<=n:
			myPrimes[j]=False
			j=j+i	
			
# part one: there are 20 different ways to replace 3 characters- i've written them manually
# but you could probably figure out a way to do this with a loop 
for k in range (100000,999999):
	if myPrimes[k] == True:
		text = str(k)
		string=[""]*20
		myCount=[0]*20
		for l in range (1,10):
			n = str(l)
			a=text[0:1]
			b=text[1:2]
			c=text[2:3]
			d=text[3:4]
			e=text[4:5]
			f=text[5:6]
			string[0]=n+n+n+d+e+f
			if myPrimes[int(string[0])]==True:
				myCount[0]+=1
			string[1]=n+n+c+n+e+f
			if myPrimes[int(string[1])]==True:
				myCount[1]+=1
			string[2]=n+n+c+d+n+f
			if myPrimes[int(string[2])]==True:
				myCount[2]+=1
			string[3]=n+n+c+d+e+n
			if myPrimes[int(string[3])]==True:
				myCount[3]+=1
			string[4]=n+b+n+n+e+f
			if myPrimes[int(string[4])]==True:
				myCount[4]+=1
			string[5]=n+b+n+d+n+f
			if myPrimes[int(string[5])]==True:
				myCount[5]+=1
			string[6]=n+b+n+d+e+n
			if myPrimes[int(string[6])]==True:
				myCount[6]+=1
			string[7]=n+b+c+n+n+f
			if myPrimes[int(string[7])]==True:
				myCount[7]+=1
			string[8]=n+b+c+n+e+n
			if myPrimes[int(string[8])]==True:
				myCount[8]+=1
			string[9]=n+b+c+d+n+n
			if myPrimes[int(string[9])]==True:
				myCount[9]+=1
			string[10]=a+n+n+n+e+f
			if myPrimes[int(string[10])]==True:
				myCount[10]+=1
			string[11]=a+n+n+d+n+f
			if myPrimes[int(string[11])]==True:
				myCount[11]+=1
			string[12]=a+n+n+d+e+n
			if myPrimes[int(string[12])]==True:
				myCount[12]+=1
			string[13]=a+n+c+n+n+f
			if myPrimes[int(string[13])]==True:
				myCount[13]+=1
			string[14]=a+n+c+n+e+n
			if myPrimes[int(string[14])]==True:
				myCount[14]+=1
			string[15]=a+n+c+d+n+n
			if myPrimes[int(string[15])]==True:
				myCount[15]+=1
			string[16]=a+b+n+n+n+f
			if myPrimes[int(string[16])]==True:
				myCount[16]+=1
			string[17]=a+b+n+n+e+n
			if myPrimes[int(string[17])]==True:
				myCount[17]+=1
			string[18]=a+b+n+d+n+n
			if myPrimes[int(string[18])]==True:
				myCount[18]+=1
			string[19]=a+b+c+n+n+n
			if myPrimes[int(string[19])]==True:
				myCount[19]+=1
		if 8 in myCount:
			print k, myCount
			break

# you have to take the answer from part 1 and run it through the string 5 pattern, and take the lowest number
text = "120383"
for l in range (1,10):
	n = str(l)
	a=text[0:1]
	b=text[1:2]
	c=text[2:3]
	d=text[3:4]
	e=text[4:5]
	f=text[5:6]
	print n+b+n+d+n+f