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test/project_euler/p006_SumSquareDiff.cpp

39 lines
810 B
C++

/* Check cf5-opt.vim defs.
VIM: let g:lcppflags="-std=c++11 -O2 -pthread"
VIM: let g:wcppflags="/O2 /EHsc /DWIN32"
*/
#include <iostream>
/*
Sum square difference
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.
Solution:
25164150
*/
int main ( void )
{
const long long n = 100;
long long s = n*(n+1)/2;
s*=s;
for ( long long i = 1; i <= n; ++i )
s-=i*i;
std::cout << s << std::endl;
return 0;
}