931 B
931 B
id | title | challengeType | forumTopicId | dashedName |
---|---|---|---|---|
5900f43e1000cf542c50ff50 | Problem 210: Obtuse Angled Triangles | 5 | 301852 | problem-210-obtuse-angled-triangles |
--description--
Consider the set S(r)
of points (x
,y
) with integer coordinates satisfying |x| + |y| ≤ r
.
Let O
be the point (0,0) and C
the point (\frac{r}{4}
,\frac{r}{4}
).
Let N(r)
be the number of points B
in S(r)
, so that the triangle OBC
has an obtuse angle, i.e. the largest angle α
satisfies 90°<α<180°
.
So, for example, N(4)=24
and N(8)=100
.
What is N(1\\,000\\,000\\,000)
?
--hints--
obtuseAngledTriangles()
should return 1598174770174689500
.
assert.strictEqual(obtuseAngledTriangles(), 1598174770174689500);
--seed--
--seed-contents--
function obtuseAngledTriangles() {
return true;
}
obtuseAngledTriangles();
--solutions--
// solution required