pe #9

gistfile1.txt

// project euler #9
// jay r bolton 1/5/2016
//
//
// 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.

// iterate over numbers [a, a+1, ..], [b, b+1, ...], [c, c+1, ...] and find the triplet that satisfies a^2 + b^2 = c^2 and a + b + c = 1000
// constraints/filters:
// - a < b < c < (1000/3)
//
// brute forcing 333 * 333 * 333 iterations will be 36926037 iterations -- we can probably cut that down...
//
// Really easy in haskell:
// [a * b * c | a <- [200..500], b <- [a+1..500], c <- [b+1..500], a^2 + b^2 + c^2 == 1000 && a + b + c == 100]

let answer = false
for(let a = 200; a < 500 && !answer; ++a)
  for(let b = a+1; b < 500 && !answer; ++b)
    for(let c = b+1; c < 500 && !answer; ++c)
      if(Math.pow(a, 2) + Math.pow(b, 2) == Math.pow(c, 2) && a + b + c == 1000)
        answer = a * b * c

console.log('answer is', answer)