1.2 KiB
1.2 KiB
id | title | challengeType | forumTopicId | dashedName |
---|---|---|---|---|
5900f4481000cf542c50ff5a | Problem 219: Skew-cost coding | 5 | 301861 | problem-219-skew-cost-coding |
--description--
Let A
and B
be bit strings (sequences of 0's and 1's).
If A
is equal to the leftmost length(A
) bits of B
, then A
is said to be a prefix of B
.
For example, 00110 is a prefix of 001101001, but not of 00111 or 100110.
A prefix-free code of size n
is a collection of n
distinct bit strings such that no string is a prefix of any other. For example, this is a prefix-free code of size 6:
0000, 0001, 001, 01, 10, 11
Now suppose that it costs one penny to transmit a '0' bit, but four pence to transmit a '1'. Then the total cost of the prefix-free code shown above is 35 pence, which happens to be the cheapest possible for the skewed pricing scheme in question. In short, we write Cost(6) = 35
.
What is Cost(10^9)
?
--hints--
skewCostCoding()
should return 64564225042
.
assert.strictEqual(skewCostCoding(), 64564225042);
--seed--
--seed-contents--
function skewCostCoding() {
return true;
}
skewCostCoding();
--solutions--
// solution required