1 files changed, 55 insertions, 0 deletions
diff --git a/largestprime.py b/largestprime.py
new file mode 100644
index 0000000..fa39904
--- /dev/null
+++ b/largestprime.py
@@ -0,0 +1,55 @@
+import PIL, math
+import numpy as np
+#Problem 3 Largest Prime Factor
+
+###INEFFICIENT METHODS###
+#def isPrime(number):
+#	if (number <=1):
+#		return False
+#	for i in range(2,number):
+#		if(number%i==0):
+#			return False
+#	return True
+
+#def prime_factors(number):
+	#primes = []
+	#for i in range(number, 2, -1):
+		#if(number%i==0):
+			#if (isPrime(i)):
+				#return i
+	#return primes
+
+
+
+def prime_factors(number):
+	primes = []
+	if (number <=1):
+		return [1]
+	a = np.ones(number)
+	a[0]=0
+	a[1]=0#not prime
+	for i in range(2,int(math.ceil(math.sqrt(number)))):
+		if(a[i]==1):
+			j = i**2 #cross out all the multiples
+			while(j < number):
+				a[j] = False
+				j+=i
+	
+	for k in range(2, number):
+		#is prime		is a factor
+		if(a[k]==1) and (number%k==0):
+			primes.append(k)
+	return primes
+	
+def lpf(number):
+	factor = 2
+	while (number > factor):
+		if(number % factor == 0):
+			number = number/factor
+			factor = 2
+		else:
+			factor +=1
+	return factor
+			
+out = lpf(600851475143)
+print out