Programming Praxis - Happy Numbers
Today's problem had to do with Happy Numbers.
I split the problem up in two parts, splitting up a number up in to digits and checking whether or not the number is a Happy Number.
The first part I implemented in two different ways.
Method 1:
def chop(x):
r = []
length = int(ceil(log(x, 10)))
if ceil(log(x, 10)) == int(ceil(log(x, 10))):
length += 1
#a(dd), s(ubstract)
for a,s in zip(range(0, length), range(length-1, -1, -1)):
temp = x/(10**s)
for i,e in enumerate(r):
pass
temp -= e * 10**(len(r)-i)
r.append(temp)
return r
Method 2:
def chop2(x):
return [int(x) for x in str(x)]
Method 2 is shorter and faster, but I really wanted to try solving it by just using numbers. String conversions feel a bit "dirty".
Then finally, checking whether a number is a happy number or not:
def isHappyNumber(x):
if x <= 0:
return False
numbers = [x]
while x != 1:
x = sum([a**2 for a in chop(x)])
if x in numbers:
return False
numbers.append(x)
return True