Can a Beholder face its Antimagic Cone behind itself?

The text for a Beholder’s Antimagic Cone ability reads as follows (MM, pg. 28):

The beholder’s central eye creates an area of antimagic, as in the antimagic field spell, in a 150-foot cone. At the start of each of its turns, the beholder decides which way the cone faces and whether the cone is active. The area works against the beholder’s own eye rays.

The ability states the beholder decides which way the cone faces, and provides no limitations, so would the Beholder be able to face the cone directly behind itself?

Intuition behind this specific algorithm for time series

Going through the EPI book and I need some help understanding this part.

There’s a problem, 5.7, that deals with buying and selling twice over a single time-series in order to maximise profit. The input is given as a list of ints. The example they give is:

[12, 11, 13, 9, 12, 8, 14, 13, 15] 

So here the maximum profit from a single buy-sell event is 7; buy at 8 and sell at 15. From two buy-sell events it is 10; buy at 9, sell at 12 and buy at 8, sell at 15.

The intuition for a single buy-sell is simple where we just keep track of the minimum element in the list and the difference between the minimum and the current element is the profit.

What I don’t understand is how the double buy-sell formula works. The book proposes a solution where two passes are made through the data, a forward and a backward pass. The forward pass uses the same formula as above (single buy-sell), but the backward pass starts at the back of the list and keeps track of the maximum instead. The profits of the backward pass are stored in an array and added to the profits of the forward pass with $ M[i] = F[i – 1] + B[i]$ , and where $ F[-1] = 0$ .

Why does the backward pass keep track of the maximum, and how does the formula ensure that we won’t buy before the second sale?

Here is the solution code given:

def buy_and_sell_stock_twice(prices: List[float]) -> float:     max_total_profit, min_price_so_far = 0.0, float('inf')     first_buy_sell_profits = [0.0] * len(prices)     for i, price in enumerate(prices):         min_price_so_far = min(min_price_so_far, price)         max_total_profit = max(max_total_profit, price - min_price_so_far)         first_buy_sell_profits[i] = max_total_profit     # Now for the backwards pass.     max_price_so_far = float('-inf')     for i, price in reversed(list(enumerate(prices[1:], 1))):         max_price_so_far = max(max_price_so_far, price)         max_total_profit = max(             max_total_profit,             max_price_so_far - price + first_buy_sell_profits[i - 1])     return max_total_profit 

For some reason the code highlighting isn’t showing up on the draft even though I specified the language.

I broke down the iterator in the reverse pass and it creates:

[(8, 15), (7, 13), (6, 14), (5, 8), (4, 12), (3, 9), (2, 13), (1, 11)] 

The expected backwards pass result is also provided for the sample data:

B = [7, 7, 7, 7, 7, 7, 2, 2, 0] 

Looking through the code I can see how the algorithm can be used to populate B. What doesn’t make sense is why this backwards pass guarantees the max profit, how it guarantees sane buys and sells, and what the intuition is for doing it this way.

I looked at similar questions but they provide different solutions which work great but don’t provide any insight on the book’s solution. The book is also not readily available online so there is less content on the material.

Intuition Behind Moore’s Law

I recently read a Quora Answer (The one by Richard Muller) by a reputed author who said that how Moore’s Law still holds when people expected it to deviate and had given explanations as to why it wouldn’t hold for a long time.

I want to understand how did Gordon Moore come up with this law. He saw data for a few years but how was it sufficient to make such a claim and say that it would hold for a long period of time.

If a player run behind a wall, use Hide, then comes out, they will still be “hidden”? [duplicate]

This question already has an answer here:

  • Can the rogue repeatedly hide in combat to sneak attack the same enemy? 9 answers

If a player run behind a wall, use Hide (as an action), then comes out, they will still be “hidden”?

I’m the DM at this table (Lost Mine of Phandelver, 5e), and our Halfling Rogue, is doing that to gain the advantage attack from Unseen Attackers.

His actions goes like following:

  1. Run behind a wall (in the corner or behind the stairs for example).
  2. Use Rogue’s Cunning Action to Hide as a bonus action.
  3. On his next turn, move 5 feet (just to get out of the wall) and attack (with a bow) the enemy with advantage from Unseen Attackers.
  4. repeat.

When he uses the hide action, I ask him for a Stealth check, then I compare with the enemies Passive Perception.

Because he is a Rogue with +7 stealth, is very hard to actually detect him.

Are we using Hide correctly? Should I keep letting he have the Unseen Attackers advantage?

What is the logic behind delete other-end chat?

I am design a social network site. One of the most important feature of site is chatting.

But I have no idea that should I give feature to delete messages including other end too. (Eg: If A send a message to B, should I allow A to delete just his own message or even with B message).

Let say two sample popular apps.

  1. WhatsApp : When you send a message, you can delete message even the other-end…

  2. Facebook : You can delete only your own message. Even you delete message, still other end can read it.

Above both companies handled by same company. But they use two different way.

What is the logic behind it?

How does Hulu know my local time when I am behind a VPN?

To see what would happen, I attempted to access Hulu from a VPN outside the US. As I expected, Hulu detected the VPN. My understanding is that this is because Hulu is aware of the IP address ranges that belong to known VPNs. However, what caught me by surprise was Hulu’s ability to display the time of the incident in my local time zone. How can this be possible? How does Hulu know in which time zone I am actually located?

Flutter : How to get Flutter packages behind a corporate proxy?

Error

Got TLS error trying to find package cupertino_icons at https://pub.dartlang.org

Tried adding https_proxy=USERNAME:PASSWORD@hostname:port as system variable also tried DART_VM_OPTIONS="--root-certs-file={path.to.certificate.file}" but doesn’t help

PS: For Android Gradle I’ve generate a new keystore from dependencies websites certificates and injected it into gradle.properties to make it work.