原题链接 http://projecteuler.net/problem=9

Special Pythagorean triplet

A Pythagorean triplet is a set of three natural numbers, a < b < c, for which,
a² + b² = c²
For example, 3² + 4² = 9 + 16 = 25 = 5².

There exists exactly one Pythagorean triplet for which a + b + c = 1000.
Find the product abc.

特殊的毕达哥拉斯三元组

一个毕达哥拉斯三元组指的是三个自然数， a < b < c ,且

a² + b² = c²

^例如，3² + 4² = 9 + 16 = 25 = 5².

有且只有一组毕达哥拉斯三元组满足 a + b + c = 1000.

求abc的乘积

解答：

将 c = 1000 - a - b代入a² + b² = c²

得到1000 (a + b) = 500000 + a b

暴力找到满足这个条件的a和b.