Euler 6

So the other night I was a bit bored and decided to do something to pass the time. I first came across Project Euler a while ago, but had never gone further than problem #1. Boredom is a great motivator and I went through problems #2 thru #9 last night and I decided to post my solutions in search of better ones. Feel free to comment with your suggestions.

Project Euler’s Problem #6 statement is —

The sum of the squares of the first ten natural numbers is,

[pmath]1² + 2² + … + 10² = 385[/pmath]

The square of the sum of the first ten natural numbers is,

pmath² = 55² = 3025[/pmath]

Hence the difference between the sum of the squares of the first ten natural numbers and the square of the sum is [pmath]3025 – 385 = 2640[/pmath].

Find the difference between the sum of the squares of the first one hundred natural numbers and the square of the sum.

Can’t be more straightforward than that, really.

sqr_sum = 0
num_sum = 0
for i in range(1,100 + 1):
        num_sum += i
        sqr_sum += i**2

num_sum = num_sum**2
print sqr_sum - num_sum

I’m pretty sure Niemeyer could rewrite this in one line, but whatever. This runs in 0.015s.