Project Euler

[GrandizerII]

Ahh, I see what you mean.

You want to just initialize variables.

I think Python only allows you to do that with lists and tuples.

No, you can initialize variables with Python. What you did inside the procedure/function in Python code (a = 5) was an example of initializing, right?

Anyway, I can't remember why I wished variables in Python could just be declared/defined without initial assignment, but I did just learn something new in Python. Apparently, you can test for whether or not a variable has been defined using globals() or locals().

For example:

Code:

v = 0

if 'v' not in globals():
    print 'v not defined'
else:
    print 'v defined'

It won't throw an error at you for not defining v if you didn't. But note that you have to wrap quotes around the 'v' for this to run without errors.

[SteelCurtain]

Well, after my code for #12 ran for about 3 hours on my monster machine, I got the right answer...

Not exactly efficient, but it worked... :S

[GrandizerII]

Well, after my code for #12 ran for about 3 hours on my monster machine, I got the right answer...

Not exactly efficient, but it worked... :S

If this is still on an online IDE, this must be a good one. 3 hours is very impressive.

Since you solved the triangle number problem, did you just count all the factors less than sqrt(n), where n represents each triangle number checked? And multipled by two for non-perfect squares, and additionally added a 1 for perfect squares?

[SteelCurtain]

I'm now using IDLE, the Python IDE that comes packaged with Python. My code was rather simple, I just checked the number of divisors for each triangle number until one had more than 500 divisors. I think it was like 8 lines of code w/o the function def.

The next few were easy, I'm up to number 17. This one isn't hard, but writing the code is time consuming.

[SteelCurtain]

Problem #17 was easy in theory, required a lot of debugging...

Code:

def main():
    tot = 0

    for i in range(1, 1001):
        n = str(i)
        
        if len(n) == 1: #one digit
            tot += ones('0', n[0])
        elif len(n) == 2: #two digits
            tot += tens(n[0], n[1]) + ones(n[0], n[1])
        elif len(str(i)) == 3: #three digits
            tot += hundreds(n[0], n[1], n[2]) + tens(n[1], n[2]) + ones(n[1], n[2])

        else: #add letters for 'one thousand'
            tot += 11

    print(tot)


def ones(tens, ones):
    if tens == '1':
        return 0
    else:
        if any(ones == x for x in ['1', '2', '6']):
            return 3
        elif any(ones == x for x in ['4', '5', '9']):
            return 4
        elif any(ones == x for x in ['3', '7', '8']):
            return 5
        else:
            return 0

def tens(tens, ones):
    if tens == '1':
        if any(ones == x for x in ['1', '2']):
            return 6
        elif any(ones == x for x in ['5', '6']):
            return 7
        elif any(ones == x for x in ['3', '4', '8', '9']):
            return 8
        elif ones == '7':
            return 9
        elif ones == '0':
            return 3
    elif any(tens == x for x in ['2', '3', '8', '9']):
        return 6
    elif any(tens == x for x in ['4', '5', '6']):
        return 5
    elif tens == '7':
        return 7
    else:
        return 0
    
def hundreds(hunds, tns, ons):
    if (tns == '0' and ons == '0'):
        return 7 + ones('0', hunds)
    else:
        return 10 + ones('0', hunds)

[GrandizerII]

Problem #17 was easy in theory, required a lot of debugging...

Code:

def main():
   tot = 0

   for i in range(1, 1001):
       n = str(i)
       
       if len(n) == 1: #one digit
           tot += ones('0', n[0])
       elif len(n) == 2: #two digits
           tot += tens(n[0], n[1]) + ones(n[0], n[1])
       elif len(str(i)) == 3: #three digits
           tot += hundreds(n[0], n[1], n[2]) + tens(n[1], n[2]) + ones(n[1], n[2])

       else: #add letters for 'one thousand'
           tot += 11

   print(tot)


def ones(tens, ones):
   if tens == '1':
       return 0
   else:
       if any(ones == x for x in ['1', '2', '6']):
           return 3
       elif any(ones == x for x in ['4', '5', '9']):
           return 4
       elif any(ones == x for x in ['3', '7', '8']):
           return 5
       else:
           return 0

def tens(tens, ones):
   if tens == '1':
       if any(ones == x for x in ['1', '2']):
           return 6
       elif any(ones == x for x in ['5', '6']):
           return 7
       elif any(ones == x for x in ['3', '4', '8', '9']):
           return 8
       elif ones == '7':
           return 9
       elif ones == '0':
           return 3
   elif any(tens == x for x in ['2', '3', '8', '9']):
       return 6
   elif any(tens == x for x in ['4', '5', '6']):
       return 5
   elif tens == '7':
       return 7
   else:
       return 0
   
def hundreds(hunds, tns, ons):
   if (tns == '0' and ons == '0'):
       return 7 + ones('0', hunds)
   else:
       return 10 + ones('0', hunds)

If you want to see my code, go to Page 8 in the corresponding thread and it should be the 15th post. Country is Australia, I'm right after the Chinese dude.

[SteelCurtain]

Nice. It looks like you built a string for each number, then counted the letters? I like that approach.

[GrandizerII]

Nice. It looks like you built a string for each number, then counted the letters? I like that approach.

Yep, and two lists for digits, teen numbers, and multiples of ten.

A bit long, but I never cared about longevity, just as long as the code runs well and doesn't crash.

[GrandizerII]

This nerd has just reached problem 41.