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.
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
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
The source can also be found on Bitbucket.