Hacker Newsnew | past | comments | ask | show | jobs | submit | alexee's commentslogin

Suggestion to make it with lesser scope, but with verifiable contracts, so you can automatically verify that it was done. I'd actually use that service myself :)

For example: 1) Run 10K on Strava. 2) Solve programming challenge on Codeforces/TopCoder. 3) Pass coursera class. 4) Have X bitcoins on your wallet 5) Check-in in some specific location.


I think there is an Oracle problem here with trying to bring in data from external services

https://www.slideshare.net/mobile/InfoQ/blockchain-the-oracl...


Online accredited bachelor degree in CS, it seems there is a lot of resistance in this area too, why it takes so long for Coursera/Udacity to implemented this?


On a related topic, I was looking for a rental car and was googling related keywords, and then 30 minutes later chat bot from some car company messaged me on Facebook. Can someone explain how it is possible, how did they know my Facebook account?


to your account yes, but not if you want to send money to your friend or employee.


I wish they would issue credit cards soon. Every time I pay with credit card while travelling, my bank charges 1.5% for each transaction, in addition to bad conversion rate.


If you're in the UK, have a look at Monzo. Not a credit card, but very useful to use abroad. They don't charge a transaction fee when abroad, and the currency conversion is tracked to the MasterCard rate (whereas other providers tend to do card issuer + their own cut on top).

Result is it's very cheap to use abroad. :)


They actually plan to start charging for this because ATMs charge them:

£200 free allowance per month, 3% charge for withdrawals thereafter everywhere outside the UK

From here: https://monzo.com/blog/2017/09/13/atm-fees-abroad/

I would have just transparently passed on whatever the ATM charges rather than this weird 3% fee.


I'm a Monzo user and really unhappy to find this out. I spend most of my time in mainland Europe and the free transactions and no ATM fees are the only reason I am a user.

Can anyone comment on how Revolut compares? One pain point is that I always get asked if I want to pay in GBP or EUR, or even the cashier selects without asking me, in which case I get massively ripped off if they select GBP. With Revolut will the card look like a EUR card whilst travelling in the Eurozone?


For overseas ATM withdrawals:

Monzo (After 18th December): £200/month, 3% thereafter (https://monzo.com/blog/2017/10/17/atm-limits-announcement/)

Revolut: £200/month (£400 with Premium), 2% thereafter

Starling: No charge

Not sure about any of the other challenger banks, I've only used Monzo on a regular basis.


I just used a Revolut card during a two week trip around Iceland. It worked fantastically well. Iceland's interesting as some places charge in Krona, some in Euro, but in either case I was charged the live mid-market rate to the GBP with no extra spread or fees.

You're also allowed to withdraw roughly £200/month worth of cash (any supported currency) without any fees. Beyond that there is a charge, I can't remember how much offhand but it's not too crazy.

The one problem I had with the card was at their petrol stations. Most are self-service and require the card to be pre-authed before the fuel will start being pumped. Revolut doesn't support this so I had to use another card or find stations where I could pay in store.


Same problem with petrol stations in the USA. Most were pay-at-pump and didn't accept the card.


I've got money in GBP, EUR and USD in a Revolut debit card. I've used it on ATMs in mainland Europe and continental US without problems.


Well Santander are now charging a 5 euro fee; Sabadel have been charging 1.50 for at least the last year.


With Revolut cards?


Yes


you get the same thing with revolut.


Unfortunately, from the 18th December, that's stopping: https://monzo.com/blog/2017/10/17/atm-limits-announcement/


It's only for ATM withdrawals. If you are in first world country where card payments are well integrated this is not issue for you. Granted, in many developing countries you need cash so this will be issue.


Haha, have you never been to Germany? Tons of places still don't take credit cards.


I'm from EU (Slovakia) and not that far from Germany but surprisingly I have never been to Germany (not counting transit when I traveled through Germany in a train/bus or had to change flight) for some reason. I have always wanted to go but somehow I find places I want to go to more all the time so my travel to Germany keeps getting pushed down the list :D


Maybe 2-3 years ago, but at least in the cities the card acceptance is quite good. Berlin in particular and cafes in general being the exception.


… and bakeries, my god. I haven't seen a single bakery that accepts cards (EC or credit). Wanna buy €30 worth of cake to bring to work for your birthday? Nope, cash only.


Most Kamps do, some are franchise though.


I live in Munich and it still feels pretty hit and miss to me.


ATM withdrawals is the main selling point though.

There are plenty of cards in the UK that do not have a foreign transaction charge on purchases (nationwide, lloyds avios, for example).


From my experience though, Monzo has been much more reliable when traveling. It works in much more places in Asia for example. I traveled around Asia for a while before with my TSB UK debit card and it was getting declined almost everywhere, even in big cities like Hong Kong or Taipei (and yes I called TSB and told them I will be traveling Asia for few months in case they have some restrictions on debit cards in place, didn't help at all).

It got to a point I had to open local bank accounts and do wire transfers from my UK bank account to local bank accounts and use the local debit card. I just couldn't get my TSB/Lloyds card to work anywhere except high end western shops like Apple Store.


My use case is frequent trips to Sydney for work - a surprising number of cafes and restaurants there are cash only.


Hmm, that's surprising. I have traveled a lot in Asia (never to Australia though) and from that experience I know a lot of Asia is still cash based but Australia I'd expect every coffee / convenience shop to accept Visa/Mastercard.


That is fascinating. As someone who lives in Sydney's outer suburbs, I simply never need cash. For anything. It's almost the exact opposite of Germany, where I lived for most of the last 5 years.

Was your experience all within the inner city?


Mostly yes - around George St. for work.

For sure many coffee shops and convenience stores accept card, but I definitely find myself having to pay cash quite often (just for instance, the laksa place on Hunter street).


From Dec 18 Monzo will start charging fees for cash withdrawals abroad though. Which is relevant for people traveling to cash based countries (many in Asia) where cards only get accepted in high end stores and restaurants.


I was considering them until they changed their name. I just can't get over it.


And what was their old name?


Mondo. But it turns out there were some copyright issues (some other Mondo already existed) so they changed their name to Monzo.


Mondo, they had some trademark issues with it and had to change it.


Mondo -> Monzo


If you're American, there are cards that don't have a foreign transaction fee, like the Capital One Quicksilver Visa or Chase Amazon Visa.

Schwab's checking accounts are also great for this, the ATM card reimburses ATM fees and has no foreign transaction fee for pulling out cash.


Pretty much all the airline cards have zero foreign currency fees. They still have less than perfect exchange rates though.


Depending on where you are from there might a better alternative.

In Europe, you have Revolut, N26 and Monzo which gives you a prepaid or debit MasterCard. Instead of the higher foreign transaction bank fees you will get either Mastercard’s or interbank rates, which is so much better than your traditional bank exchange rate.

I have tried to list some options here: https://globalmoneyapp.com


Revolut have appalling customer service. I have let a couple of rogue transactions go because it's such a hassle dealing with them.


I've heard they are planning on adding those fairly soon (in the spring of '18)


CapitalOne doesn't charge any foreign transaction fees on their credit cards.


Yeah but they charge on atm withdrawals and the exchange rate could be the banks rate depending on the card.


AFAIK, all credit cards charge high fees for cash withdrawals. You should never do a cash advance on your credit card. Use a debit card for that.


CapitalOne for credit cards, Schwab Bank for ATMs


Use Revolut, if you're in the UK.


If you google stem cells + <disease name> you can find <promising> research for almost any disease, can anyone explain in simple terms, what is so magical in stem cells therapy?


My layman's understanding is that stem cells have not yet 'differentiated' into a specialised cell type which makes them useful for many different types of treatments.

Edit: so you can use them to create "healthy" versions of whatever you need.


I was asked something like this in Amazon SE interview - find something without using loops, the answer was to use recursion. Sigh.


Isn't there an actual distinction here -- induction versus co-induction?

I would argue that a loop constructs an answer, while recursion deconstructs input.

There's a duality, so you can port algorithms between the two models, but there is an actual distinction.


I don’t see what recursion/loops have to do with constructing output or dividing and conquering input.

For one thing, all loops can be trivially unrolled into a tail-recursive function that most languages will trivially transform back into a loop. Clearly these transforms have no bearing on the nature of the computation.

If asked such a question, I’d probably just use goto. (Bonus points if candidates use a goto on one part of one question I ask, since it saves a minute or two of whiteboard cut and paste, BTW).


> For one thing, all loops can be trivially unrolled into a tail-recursive function that most languages will trivially transform back into a loop.

That there's a transform between them doesn't make them the same thing, it makes them possible to use for each other in programming. You even seem aware that there's still a distinction -- you're just not sure why it matters.

> Clearly these transforms have no bearing on the nature of the computation.

Depending on the nature of the job, not understanding why you can transform between loops and recursion is big points off. (You can go back and forth because while not the same thing, they're duals, which means you'll be able to find similar structures in both for certain classes of problems.)

That's why you need to understand what induction vs co-induction is -- so you can prove things about the transforms between them, such as that it doesn't impact the result to change the algorithm in a particular manner.

Similarly, you're only talking about really simple inductive or recursive behaviors -- what about complex cases? Are all inductive structures transformable to co-inductive (or the other direction)? What does it do to computational complexity when you make the transform?

That there's an uninteresting kernel in the transform doesn't make the entire transform trivial -- it just means you're only used to working in the "well-behaved" portion of it. (And that there is such a kernel is itself an interesting fact about computation!)

> Clearly these transforms have no bearing on the nature of the computation.

Just to reiterate how off-base I find this comment: there's entire huge collaborations in mathematics and academic computer science exploring the nature of those transforms because understanding how they can be applied is essential for moving forward with things like mechanically/formally verified software.

I get that not everyone is going to know that distinction and its impact -- but the distinction absolutely matters. As you astutely point out, it's used by compilers routinely -- and they certainly need to be sure the transform is well-behaved in the cases they apply it!


You said that recursive and iterative computations are fundamentally different. I pointed out a class of recursive and iterative algorithms that are equivalent to each other. That class disproves your statement.

I’m not sure what you’re trying to get at...


I'm actually not sure what you're getting at -- the logic you just presented is "the primes and evens are the same set of numbers because both contain 2".

Assuming you mean the and not a, they're still not the same, as equivalent algorithms need not be identical. Example: 5-3 and 1+1 both compute the result 2, making them equivalent but non-identical algorithms.

There's a way to transform any subtractive recipe for a number into an additive recipe so they're equivalent classes, but addition and subtraction aren't identical as operations.


Why do you think it isn't there? Actually I bought Apple watch series 2 for exactly this reason, running without a phone. It has everything you need (GPS+heart rate monitor+music), and you can even have podcasts with third-party apps.


Wasn't the whole article about how standalone podcast apps on the watch aren't possible? What 3rd party apps allow playing podcasts on the Watch without iPhone?


There may be some half assed solutions, the article was why a good standalone podcast app isn't currently possible.


did you know about Watchcast[1]? It's been offering offline Watch podcast playback long before Marco failed at the feature and requested new APIs...

[1] https://brianmcburney.github.io/


Watchcast has the same issues Marco brought up. Developers should not condone Apple's overly-aggressive platform limitations by sacrificing good UX just to release a feature.


at least "What is the European Union?" when voting for brexit would be enough.


That's a good (and presumably unintentional) demonstration of the problem - the European Union is a hugely complex, very political beast and the right answer to that question depends heavily on your political frame of reference and priorities. Even just the free trade-related aspects can be accurately described either as giving up control of our own laws and regulations to a centralized bureaucracy or enabling trade by removing non-tariff barriers depending on how you want to frame them - since almost all non-tariff barriers other than differences in regulations are banned by WTO rules they're the same thing, one description just emphasises the benefits and the other the downsides. (I've even seen a certain FT writer who insists he's not pro-EU use both framings - the positive one when discussing the EU and the negative one when discussing post-Brexit trade deals outside the EU.)


My father is 59 and started to learn programming half a year ago. So far I was giving him algorithmic tasks to learn basic language constructs, he is now comfortable with basic Java and is able to solve most of easy problems from programming contests. And idea where to go from here? I don't think solving more difficult problems (like that involving algorithms or creative thinking) would make sense at this point. I tried to give him simple GUI project (tick-tac-toe in Swing), this kind of worked with lots of my help, but of course it was badly designed with model-view mixed, and he is unable to understand design pattern concepts at this point.


I guarantee you that if your father is 59, that at some point in his life he's found a way to be more efficient at whatever his workload was at the time than a raw beginner. Design patterns are exactly that: patterns of efficiency.

The terribad thing about them is that they don't often explain why they are more efficient than the the naive path.

I'd recommend that you pose a series of tasks to your dad, and work with him to build them out, rebuilding them several times if necessary, to start that deep understanding of the art. Adopt a posture that this work is critical, and that you are working together. You'll both learn why as you do it.


Give him a real problem to work on. It doesn't have to be big, but it has to be directly relevant to his life. Solving toy problems for fun is a good start, but to get further engagement, you need a reason to be doing x, y, or z.


Guidelines | FAQ | Lists | API | Security | Legal | Apply to YC | Contact

Search: