<section id="description">
Let E(x0, y0) be the number of steps it takes to determine the greatest common divisor of x0 and y0 with Euclid's algorithm. More formally:x1 = y0, y1 = x0 mod y0xn = yn-1, yn = xn-1 mod yn-1
E(x0, y0) is the smallest n such that yn = 0.We have E(1,1) = 1, E(10,6) = 3 and E(6,10) = 4.
Define S(N) as the sum of E(x,y) for 1 ≤ x,y ≤ N.
We have S(1) = 1, S(10) = 221 and S(100) = 39826.
Find S(5·106).
</section>

function euler433() {
  // Good luck!
  return true;
}

euler433();


index

Задача 433: Шаги в алгоритме Евклида

Problem 433: Steps in Euclid's algorithm

<code>euler433()</code> should return 326624372659664.