Project Euler Problem 14 Solution with Python

pep14.py

#http://radiusofcircle.blogspot.com

#time module for calculating execution time
import time

#time at the start of program execution
start = time.time()

#dictionary with all the values initialized to 0
dic = {n: 0 for n in xrange(1,1000000)}

#Entering the values of 1 and 2
dic[1] = 1
dic[2] = 2

#for loop find find the size of collatz sequences
for n in xrange(3,1000000,1):
	
	#counter to count the size for each iteration
	counter = 0
	
	#original number
	original_number = n

	#while loop to do collatz iterations
	while n > 1:

		#check if the number is a previous sequence
		if n < original_number:

			#Size of collatz sequence for the iteration
			dic[original_number] = dic[n] + counter
			break

		#collatz sequence conditions
		if n%2 == 0:
			n = n/2
			counter += 1
		else:
			n = 3*n+1
			counter += 1

#dic.values() will give the values of the dictionary
#list.index(some_number) will output the index
#of the number. As the index starts from 0
#we are adding one to the index.
print dic.values().index(max(dic.values()))+1

#time at the end of execution
end = time.time()

#printing the total time of execution
print end-start