Tim Varley Tim Varley

Euler 006 ruby Solution

Sum square difference
Nov 8, 2015
3 minute read

Problem

https://projecteuler.net/problem=6

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

\[1^2 + 2^2 + ... + 10^2 = 385\]

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

\[(1 + 2 + ... + 10)^2 = 55^2 = 3025\]

Hence the difference between the sum of the squares of the first ten natural numbers and the square of the sum is: \(3025 − 385 = 2640\).

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

Answer: 25164150

Solution

euler006.rb

#!/usr/bin/env ruby
def sum_squares(limit)
  sum_square = 0
  square_sum = 0

  (0..limit).each do |i|
    sum_square += (i * i)
    square_sum += i
  end
  (square_sum * square_sum) - sum_square
end

puts sum_squares(100) if __FILE__ == $PROGRAM_NAME

See Also

# cpp go java php ruby rust javascript
1
2
3  
4    
5    
6      
7          
8          
9          
10          
11          
12          
# cpp ruby
13
14
15
16
17
18
19
20  
21  
22  
23  
24