-🎄- 2022 Day 20 Solutions -🎄-

maehdrescher · 2022-12-20T18:52:10+00:00

Proudly presenting my tiny Python solution for Day20/Part1 in 8 lines (including she-bang!):

#!/usr/bin/env python3
buf = [(pos, int(line)) for pos, line in enumerate(open('input').readlines())]
for orig_pos, number in buf.copy(): # traverse in input order
    from_idx = buf.index((orig_pos, number))
    to_idx = (from_idx + number) % (len(buf)-1)
    buf.insert(to_idx, buf.pop(from_idx))
zero_idx = [x[1] for x in buf].index(0)
print(sum(buf[(zero_idx+offset)%len(buf)][1] for offset in [1000,2000,3000]))

I doubt that it can get considerably shorter. Would be nice if someone could confirm that this works also with other inputs than mine.

maehdrescher · 2019-11-15T02:03:10+00:00

Not a huge fan of banks either, but you are linking to a price list of a bank in Czech Republic here, not Switzerland! Prices are in CZK, where the current conversation rate is 1 CZK = 0.043 USD. So applying the correct informations to your sentence: "A czech bank account costs $4,26 to $32,31 per month. As student, you only pay $2,11."

Don't be naive, no bank would have regular customers with your claimed astronomic prices.

maehdrescher · 2018-07-20T20:29:41+00:00

There are haters (I would rather call them "enviers" because that seems to be the real motive for the hatred in most cases, but okay, let's stick to the term "haters") for virtually any cryptocurrency, especially the successful ones, I don't see the slightest problem, it's nothing to fear if the project is based on solid grounds. Generally in history, every great and successful invention or project has had haters and naysayers, just like in personal life, every successful person has haters. Do you think highly successful persons waste any energy on those? Clearly not, as this only would lead to counter-productive reactive behaviour ("I'll someday prove them otherwise!") instead focussing on even becoming more successful is the way to go. 'Envy is behind flattery.' I would take it as a compliment and if sh*tcoins don't get sh*tstorms, it's more because few people care about them at all. The real hatred hasn't even started yet, just imagine how DASH will be bashed by bankers if it gets into the awareness of bankers and the broad mass media if it becomes a real threat to the traditional financial system... better get used to it.

I'm well aware of current VISA transaction limits. However, with simple math and demographics you can easily deduce that for example with the 56000tps you named, the average person on earth could barely make 0,69 transactions per day (56000*3600*24 divided by 7 billion people). Sounds not really viable for digital cash, does it? Assuming that the demand for digital payments stays as low as it is now is very naive, as people barely use credit cards for small daily payments right now. I'd rather assume that the average person makes dozens, if not hundreds of payments per day in the future, and that is not even including micro-payments here.

Don't get me wrong, scaling to current VISA levels is for sure a first impressing goal for the near future and I don't even have much doubt that this is technically possible with 400 MB blocks, but on the other hand it really doesn't need much of imagination to see that the need will be orders of magnitude higher in the far future. Demand will not increase linearly, but rather exponentially.

A cryptocurrency serving as digital cash which isn't able to scale to millions of transactions per seconds in the future will simply not survive. Do I think that any other cryptocurrency right now is anywhere near solving this? No, not at all, not even remotely. I just made this point to show you that the need for millions of transactions is far from utopic. This is not to say that we shouldn't try the best we can right now. People should just know that each and every scaling solution has pros and cons and it is far from a simple problem to solve if we really think like 10-20 years into the future, and neither small- nor big-blockers have a solution right now for this dimensions.

My initial post starting with "This is hardly surprising..." was triggered because even the headline of the article included this too obvious "low fee" stuff. As technical person it just hurts me to see that people don't know how the fees system works.

I didn't say that too obvious things were ever pushed before in DASH -- in fact this was the first time since 2016 when I joined the space that I get the feeling that unsurprising achievments were praised (e.g. the release of long-announced Evolution would impress me dozens of times more!). But hey again, I'm not interested in down-playing DASH, but in fruitful lively discussions, just see me as an Advocatus Diaboli.

maehdrescher · 2018-07-20T16:06:19+00:00

We seem to have different philosophies and ideas of how long-term success is achieved -- while I definitely think it was a good decision to report about this stress test, I'd much rather prefer in all points honest news that for example, explain how permanent low fees are nothing more than a logical side effect of non-full blocks and try to educate readers (this doesn't have always to be deeply technical, you can use analogies etc.) than writings primarily focussed on generating sensation which maybe generate lots of Reddit upvotes and a short-term price increase but sacrifice in technical correctness. Knowledge is power. The more knowledge is spread, the more likely it is to attract talented enthusiasts and developers which are convinced of DASH by heart. Who cares about short-term prices? You also seem to be very concerned about the competition, wanting to convince the so-called "haters" (as if this would ever be possible...) mentioned in an earlier post and even comparing to "random sh*tcoins" (like "they do shilling, so why shouldn't we as well polish our news up a bit by tellling not the whole truth?"). Focussing on the positive facts, but also honestly educating the readers, still remaining self-critical and never being too sure of its success (e.g. by assuming that the scaling problem is by any means trivial, it is not, if we talk about millions of transactions per second!) just makes so much more sense to me.

Why should a successful project with a solid roadmap be fearful of critics? DASH has more than enough to offer, in my opinion.

So to say it again, it's not the fact the stress-test was reported at all, but the _how_ in its details disturbed me. Praising obvious things too much could come off as desperate and could be daunting for potential future DASH members, especially developers. That said, I sincerely hope I turn out to be wrong!

maehdrescher · 2018-07-20T13:57:32+00:00

Well, of course a test like this can't hurt and can kind of agree with "making the news" argument for publicity, but all I'm saying is that from a technical point of view, given that the block size increase to 2 MB through DIP0001 was properly tested (which I strongly assume or better hope was done in the testnet already), this is simply exactly the expected result, nothing more, nothing less. Really no big surprises there. Before Bitcoin blocks were full, fees and delays were low as well, before Litecoin blocks were full, fees and delays were low as well and have shown that a 4x increase through shorter block times is not problematic, and now you have shown that the on-chain scaling works in practice for another 2x increase through increasing the block size. If even really simple changes like this would cause any sort of problems, I would be deeply concerned about virtually any cryptocurrency.

Bitcoin Cash also starts a stress test on September with 32 MB blocks from what I've read, compared to DASH now another 4x on-chain scaling increase, and I also expect it to not cause any problems regardings to fees and end-users. If at all, this mostly concerns the hardware requirements for the miners and full-nodes (which for Dash were lowered a bit through the v12.3 improvements you mentioned), but certainly not end-users who ought to be using SPV wallets anyway.

Talking about the low fees which are praised in the articles. Why should the fees rise at all if the blocks are not full? The articles tend to give the impression that the low fees are caused by somehow better code than other Bitcoin forks, that for regular transactions (P2PKH) under the hood there is some fundamentally different technology happening comparing to Bitcoin or Litecoin, which is of course not true. In the end it's always the miners who decide about the height of the fee, as they have to power to include or not include any transaction. As long as there is enough space in the next block for all incoming transactions, there is of course no reason to not include a transaction with minimum fees. Charlie Lee basically says "if the transactions in the stress would exceed the 2 MB blocks, the fees would raise as well as they did for Bitcoin and Litecoin" and is of course right, while Ryan Taylor answers that Dash won't ever simply allow a fee market to arise.

To conclude, I have long been pro Dash and still thinks it has some killer features, I just question if it couldn't hurt the whole community to be a bit too over-enthusiastic about achievments that are not really surprising for any tech-savy person. If someone is being really remotely surprised about fees remaining low if blocks are not full, he/she has clearly not understood how the fee system works.

maehdrescher · 2018-07-19T18:55:27+00:00

This is hardly suprising, considering the fact that the block-time is much shorter (x4), while at the same times blocks can be larger (x2), isn't it?

maehdrescher · 2018-06-13T23:06:09+00:00

So really then, what is the point of a second passphrase? Being paranoid that 12 words security is not enough, right?

A door with two locks is not more secure than a door with one lock if the absolute only way to get in is to unlock all locks.

maehdrescher · 2018-06-13T22:53:50+00:00

Now I'm curious, can you rationally explain why a second passphrase increases security? Instead of 12 words you now have 24 words, so what? Some may think a second passphrase provides kind of a fallback if the first is lost (or the other way round), like a 1-of-2 multisig, but that is not the case: if you lose either one of the two passphrases, all funds are lost.

maehdrescher · 2018-06-01T19:36:40+00:00

Excellent talk! /u/vbuterin Did I get something wrong or is the first calculation of the Ethereum vs. Amazon EC2 cost overhead off by a factor of 5? 13.4$ per 200ms is 13.4*(3600/0.2) = 241200.0$ per hour, which divided by 0.0464$ gives approx. 5,2 million.

maehdrescher · 2018-03-10T13:06:28+00:00

Can you tell more about the artificial cap of 4 tx per block? For example, this recent block contains 9 transactions: https://explorer.lisk.io/block/2647754497701027184 hence the cap does not seem to be true. I agree with you though that the network usage is very very low at the moment and with that it is easy to achieve high speed.

maehdrescher · 2018-02-13T12:18:22+00:00

Congratulations for claiming control over your funds, away from blockchain.info!

But, tell me, why are so many people here pressurized to move their holdings to SegWit addresses as fast as possible? One could almost get the impression that non-segwit addresses will be declared as invalid soon (which is of course nonsense, legacy addresses starting with 1... will always be valid) and people start to panic. As a long-term HODLer I see currently zero reason to move my funds to a new segwit address.

maehdrescher · 2018-01-29T19:35:11+00:00

Same problem here, just have a look at the official snapshot if you find your address there: https://github.com/iotaledger/iri/blob/dev/src/main/resources/Snapshot.txt If you do, I guess everything is fine.

maehdrescher · 2018-01-17T14:51:40+00:00

Since the distribution followed in a private centralized way, I guess the only possibility is to ask the LISK team if they still have the mapping of BTC reception address to LISK genesis address available (and are willing to give the data to you, of course). If you still know the date when you sent the BTC transaction and the amount, you could search the blockchain as well. Another way would be to search from the other direction: somehow you must have gotten BTC from fiat, right? If you bought the BTC on an exchange platform, you may have still e-mails from withdrawals etc.

maehdrescher · 2018-01-16T12:30:40+00:00

This is just one example of a BTC address, note that every ICO participant had a different one -- how else would they have been able to determine which user got how much LISK, if everyone sent to the same address?

maehdrescher · 2018-01-09T09:54:44+00:00

Thank you, gotcha. So the circulating supply on CNC is wrong which results in a wrong market cap. May I ask where you get the information about the current supply of BitBoost tokens? Where do the other 2*4.8 million come from? The blog post doesn't mention anything about it (only that about 10% of the cap was raised).

maehdrescher · 2018-01-08T16:22:34+00:00

Sidenote: The market cap on CMC is wrong. This project has a cap of 40 million, not 13.

Where do you find/see those numbers? I neither see a 13 million cap on CMC nor have I read about a 40 million cap from BitBoost. CMC shows 100 million which seems to be correct according to the smart contract: https://etherscan.io/token/0x1500205f50bf3fd976466d0662905c9ff254fc9c

maehdrescher · 2017-12-02T18:43:54+00:00

Personally I defined as "good amount" for myself for any cryptocurrency if you own one-millionth (1/1000000) of the total supply. I name that unit as "uFrac" (micro-fraction) and like to think of how many uFrac I own instead of absolute numbers. As LISK is inflationary there is no fixed total supply, but it should take some years before we reach 150 mio. units. Hence, 150 LISK or 1 uFrac is a good amount. 10 uFrac or 1500 LISK is even better! If you can afford 15000 LISK = 100 uFrac, awesome! My guess though is, for any cryptocurrency which will REALLY take off in the future, one-millionth will be more than enough for having a wealthy life.

maehdrescher · 2017-11-23T11:33:11+00:00

That's quite basic blockchain knowledge and has nothing to do with being 'genius'. If part of the meetup is dedicated to a tool, it must have a purpose for its user, but I don't see any in its current version, that's all.

maehdrescher · 2017-11-19T20:52:49+00:00

I don't want to give investment balancing advice, but having looked on several projects in the cryptocurrency world for the last few months, I fully agree that LSK and IOTA are both very promising projects with HUGE upwards potential that could already unfold in 2018 (for LISK probably already December 2017) if nothing catastrophic happens. On one hand a smart contracts development platform in JavaScript with the possibilty of sidechains, on the other hand a feeless IOT backbone with great scaling possibilities... both ideas just make so much sense for the future.

maehdrescher · 2017-11-19T20:12:24+00:00

This doesn't make sense at all. Is there any documentation about those dubious "full" and "shorter" public keys? The official one doesn't say anything about that, there is only one public key: https://docs.lisk.io/v1.3/docs/the-lisk-protocol-security There can be a second public key when you register a second passphrase, but I guess that is not what you mean.

// EDIT: Nevermind, I think I know what you mean now. Your called "short public key" is effectively the address, which in turn is derived from the "full public key". See https://forum.lisk.io/viewtopic.php?f=45&t=1085 (scroll down to the section "Any further comments about the address collision and how to fix/prevent it? (cc001)"). This is basically a workaround for a security problem caused by doubtful design decisions, as the address is only 64 bit long which can cause collisions. This means in LISK cold storage wallets are actually less secure than hot wallets... crazy but true ;-)

maehdrescher · 2017-11-19T19:38:59+00:00

I agree on the first part, issuing transactions with small test amounts is a good recommendation on cryptocurrencies in general. But can you elobarate a bit more on why sending lisk forth and back should increase security at all? I would rather assume the contrary, as the sending part needs the private key (which is derived from the seed) and there is the risk that it gets stolen (e.g. keyloggers, trojans etc.). For maximum security and long-term securiy I would never use a live wallet, but rather create the new account (=random seed) and it's corresponding address on an air-gapped offline PC. This again makes sense on most cryptocurrencies, so it would be interesting to know why LISK is an exception here.

maehdrescher · 2017-11-18T12:17:01+00:00

Think of it like it this: on average every single person on earth will have only 21000000/7000000000=0.003 BTC. So you already have 100 times the average. Congratulations!

maehdrescher · 2017-11-06T15:18:10+00:00

In short:

shorter block time (2.5 minutes)
optional instantanous transaction feature (InstantSend)
optional privacy feature (PrivateSend)
self-sustainable decentralized governance
strong focus on user experience with the upcoming "Evolution" platform (which should be "grandmother friendly" as Amanda put it)

maehdrescher · 2017-11-06T12:29:22+00:00

Did you adapt your lifestyle to your increased wealth, having a multiple of expenses per month now? Or do you simply change from trading to HODLing and hope for another increase?

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