9 ms·

> Please do not ask me for solutions to the exercises. Even if you are [an] instructor, I will say no. That's kind of a bummer. I like to be able to check my a

> Please do not ask me for solutions to the exercises. Even if you are [an] instructor, I will say no. That's kind of a bummer. I like to be able to check my answers when teaching myself things. Am I somehow alone in that?

bryanrasmussen 8y ago
could be a monetization idea/incentive to purchase, purchase the book get unique key, use key to check in to site to see results.
- jj12345 8y ago
  This is done occasionally in algo books to encourage their adoption in cirricula (e.g. Dasgupta, etc.). As a sibling comment mentions, it's relatively easy to verify your answer for correctness in some cases. The downside of this is that it becomes difficult to assess whether students are actually learning. One way to mitigate this is to withhold answers and assist with other teaching resources like TAs. This also helps teach the aforementioned 'verification' step.
- jefferickson 8y ago
  Nope. Anything I publish will be available free.
heinrichhartman 8y ago
I have seen many people voice that complain. Personally I rarely had issues verifying a solution once I have worked through a problem. What happens much more frequently, is that I get stuck somewhere, and get tempted to look at a solution if one is provided, which in turn nullifies the achievement. In this sense, not having solutions, makes it easier for me to plough through.
- ryanmonroe 8y ago
  If you prefer not to have solutions, pretend you don't have solutions. Having solutions is strictly better (for the reader. I'm ignoring the cost of producing them to begin with)
  - nf05papsjfVbc 8y ago
    "pretend you don't have solutions" is not a realistic approach. The strength of people's conviction to this will probably fall on a bell curve and few can resist the temptation when the problems get really tough. Accounting for how humans are, I do not see how one can easily say "Having solutions is strictly better". I can easily think of cases where it is indeed better to have solutions but to say "strictly" requires a bit more diligence.
    - heinrichhartman 8y ago
      yes, exactly.
    - thrwthrw93223 8y ago
      Don’t rob the self-learner that doesn’t have access to TAs, fellow students, and professors the ability to check their work, just because someone else doesn’t have the discipline to not abuse it. Textbook solutions are good for those that aren’t in school, aren’t in formal programs and have no other way of receiving feedback. The “you should know if you’re right” mentality doesn’t necessarily fit a person that’s been working for 10-years and has been out of the academic mindset. One that is a beginner and could easily fool themselves into thinking they have a correct answer. It doesn’t allow for correction of false thinking. Anyone can think their proof is correct. But fewer beginners can properly recognize when they are wrong. This sort of mentality is a bit elitist and gate keeping.
      - kemiller2002 8y ago
        I had a girlfriend who was doing her PhD in Physics. I remember one night she and her classmates spent all night working on a problem, that was essentially unsolvable. The next day they go to class and all of them made their best attempt, but no one could complete it. The problem? The professor accidentally used the wrong metric on one of the numbers meaning that they couldn't do the steps to what should have been an easy solution. Now they noticed this, they are a smart group of people, but that's not what the problem was, so they spent hours and hours trying to solve what he gave them without any hope of actually doing it. In the end, he was like "Oh my bad," and corrected his mistake. The point of the story is that they were able to essentially ask him for the solution and they were able to check what they'd done, and in the end he made the mistake. In situations like this, he should provide the answer if nothing else to show that he didn't make a mistake in the problem set. People are fallible, no matter how brilliant you are.
- kurtisc 8y ago
  Solutions are to questions as tests are to software. For me they offer peace of mind no matter how sure I am.
kkarakk 8y ago
as is the case with all uni oriented textbooks, they can't be used alone if you don't instantly grok the content. i'm sure just searching github for a sample implementation followed by a discussion of the finer points on stackoverflow/programming reddit of choice will do you a 5 minute search gave me this - https://github.com/floyernick/Data-Structures-and-Algorithms https://github.com/floyernick/Data-Structures-and-Algorithms for algos implemented in Go. github is littered with these kindsa samples(some of them highly vetted) https://github.com/topics/algorithms-and-data-structures https://github.com/topics/algorithms-and-data-structures
dhimes 8y ago
The author probably agrees with you. He indicates that he provides solutions for most of the problems he assigns to his class.
porpoisely 8y ago
The princeton algorithm site has solutions for some of their exercises. Also they have online lectures as well along with animations, visualizations, etc. It's an excellent resource for those who want to learn algorithms. https://algs4.cs.princeton.edu/home/ https://algs4.cs.princeton.edu/home/
znpy 8y ago
The book sources are available through GitHub, you or someone else could easily fork the project and add all the content that in your opinion is missing (including answers to exercises).
p1itopre 8y ago
No, you are not. The extensive problem sets at the end of each chapter is main contribution of this work (imho). However this is not a shortcoming these days. I spend upto ~1 hour on each problem. And then I google keywords from the questions. Someone somewhere has one possible solution. Usually , this is enough to set me on the right track.
philonoist 8y ago
Solutions were stepping stones to my success. I am mature enough to not be tempted without trying out the problem. I sleep over it and then at last looking at the solution, if I ever find myself at my wit's end. That is because I have a firm understanding that there is no shortcuts to success. Having come from a third world country where cheating on oneself is delaying even the basic resources to get a job, I was raised with peers finding the 'peeping at solutions' an abhorrent act. Its a big shameful thing to do in my culture. Solutions are the way I learn the thought process of author if he arrived at the final answer in a better way. Solutions expose errors in questions. Errors and typos in Indian texts were way more a common place in questions than in solutions. There was simply not a chance for a solution to have typo or logical errors. If there are no solutions, I'd simply put it for later until I am proficient in the subject and want to try out the problems with confidence. There is always this insecurity when it comes to dealing with logic. Little things can slip in abstract thinking pretty easily. Silly mistakes take a toll. People like myself prefer to solve problems individually at our own pace. Solutions are a must for me. Of course, that 'later' almost always never comes.
jefferickson 8y ago
Hi, I'm the author. I'm honestly seriously torn about this. There is a serious tension between pedagogical needs of students in formal classrooms and the pedagogical needs of self-learners. I've chosen to aim for the former. Yes, I know it's a bummer. (From experience) providing solutions interferes with the learning process of my own students at Illinois. I have to change up homeworks and exam questions every semester, because otherwise students will look up and copy/memorize the answers instead of trying to figuring them out, which means they do worse on the exams where they HAVE to figure things out. Also, a significant majority of the requests I get for solutions are from university students who want to cheat. I do provide solutions to the homework and exam and lab problems I assign in any particular class, after the fact. (And I release those solutions publicly, despite the protests of colleagues at other universities, until the semester ends.) And I have started proving model solutions in the homeworks, so that the students know what kind of answers I'm looking for. (See the course materials page, under CS 374.) In practice, my stance is becoming increasingly moot, as more of my official solutions get uploaded to places like CourseHero and Koofers and their many foreign-language equivalents. I am very likely to include solutions for a subset of problems (maybe three or four per chapter) in a future edition. But that will take a significant amount of time, and I wanted to get something out the door.
- smarks 8y ago
  Thanks for this explanation. This is one of the things that popped out at me when I looked at the book page. The statement about not providing answers seemed quite dogmatic, and my initial reaction was, why? Turns out it's not so dogmatic, and there's a thoughtful and nuanced explanation. Perhaps you could include some of this on the book page, or provide a link to the explanation elsewhere.
  - _underflow_ 8y ago
    Completely agree - being outside academia has apparently made me ignorant to a lot of the pitfalls to actually posting said solutions. Makes perfect sense when put this way. I also really appreciate the response from the author. I forget the gurus behind books like this often have a presence here on HN.
commandlinefan 8y ago
> I like to be able to check my answers when teaching myself things. I agree, although looking at the exercises in this book, they seem to be of the form where the only way to give you the answer is you give you the full solution, and they appear to be phrased in a way that makes it easy enough to verify the answer yourself once you’ve figured out the problem. I always feel like the ideal (for me at least) are problems with numerical answers listed in the back of the book – then I can check my answer with the book’s answer; if I got 42 but they got 5, I know I made a mistake somewhere but it’s still up to me to go back through and figure out where the mistake was. It seems like most of these problems don’t lend themselves to short numerical answers like that.

bryanrasmussen 8y ago

could be a monetization idea/incentive to purchase, purchase the book get unique key, use key to check in to site to see results.

jj12345 8y ago
This is done occasionally in algo books to encourage their adoption in cirricula (e.g. Dasgupta, etc.). As a sibling comment mentions, it's relatively easy to verify your answer for correctness in some cases. The downside of this is that it becomes difficult to assess whether students are actually learning. One way to mitigate this is to withhold answers and assist with other teaching resources like TAs. This also helps teach the aforementioned 'verification' step.
jefferickson 8y ago
Nope. Anything I publish will be available free.

heinrichhartman 8y ago

I have seen many people voice that complain. Personally I rarely had issues verifying a solution once I have worked through a problem. What happens much more frequently, is that I get stuck somewhere, and get tempted to look at a solution if one is provided, which in turn nullifies the achievement. In this sense, not having solutions, makes it easier for me to plough through.

ryanmonroe 8y ago
If you prefer not to have solutions, pretend you don't have solutions. Having solutions is strictly better (for the reader. I'm ignoring the cost of producing them to begin with)
- nf05papsjfVbc 8y ago
  "pretend you don't have solutions" is not a realistic approach. The strength of people's conviction to this will probably fall on a bell curve and few can resist the temptation when the problems get really tough. Accounting for how humans are, I do not see how one can easily say "Having solutions is strictly better". I can easily think of cases where it is indeed better to have solutions but to say "strictly" requires a bit more diligence.
  - heinrichhartman 8y ago
    yes, exactly.
  - thrwthrw93223 8y ago
    Don’t rob the self-learner that doesn’t have access to TAs, fellow students, and professors the ability to check their work, just because someone else doesn’t have the discipline to not abuse it. Textbook solutions are good for those that aren’t in school, aren’t in formal programs and have no other way of receiving feedback. The “you should know if you’re right” mentality doesn’t necessarily fit a person that’s been working for 10-years and has been out of the academic mindset. One that is a beginner and could easily fool themselves into thinking they have a correct answer. It doesn’t allow for correction of false thinking. Anyone can think their proof is correct. But fewer beginners can properly recognize when they are wrong. This sort of mentality is a bit elitist and gate keeping.
    - kemiller2002 8y ago
      I had a girlfriend who was doing her PhD in Physics. I remember one night she and her classmates spent all night working on a problem, that was essentially unsolvable. The next day they go to class and all of them made their best attempt, but no one could complete it. The problem? The professor accidentally used the wrong metric on one of the numbers meaning that they couldn't do the steps to what should have been an easy solution. Now they noticed this, they are a smart group of people, but that's not what the problem was, so they spent hours and hours trying to solve what he gave them without any hope of actually doing it. In the end, he was like "Oh my bad," and corrected his mistake. The point of the story is that they were able to essentially ask him for the solution and they were able to check what they'd done, and in the end he made the mistake. In situations like this, he should provide the answer if nothing else to show that he didn't make a mistake in the problem set. People are fallible, no matter how brilliant you are.
kurtisc 8y ago
Solutions are to questions as tests are to software. For me they offer peace of mind no matter how sure I am.

kkarakk 8y ago

as is the case with all uni oriented textbooks, they can't be used alone if you don't instantly grok the content. i'm sure just searching github for a sample implementation followed by a discussion of the finer points on stackoverflow/programming reddit of choice will do you a 5 minute search gave me this - https://github.com/floyernick/Data-Structures-and-Algorithms https://github.com/floyernick/Data-Structures-and-Algorithms for algos implemented in Go. github is littered with these kindsa samples(some of them highly vetted) https://github.com/topics/algorithms-and-data-structures https://github.com/topics/algorithms-and-data-structures

dhimes 8y ago

The author probably agrees with you. He indicates that he provides solutions for most of the problems he assigns to his class.

porpoisely 8y ago

The princeton algorithm site has solutions for some of their exercises. Also they have online lectures as well along with animations, visualizations, etc. It's an excellent resource for those who want to learn algorithms. https://algs4.cs.princeton.edu/home/ https://algs4.cs.princeton.edu/home/

znpy 8y ago

The book sources are available through GitHub, you or someone else could easily fork the project and add all the content that in your opinion is missing (including answers to exercises).

p1itopre 8y ago

No, you are not. The extensive problem sets at the end of each chapter is main contribution of this work (imho). However this is not a shortcoming these days. I spend upto ~1 hour on each problem. And then I google keywords from the questions. Someone somewhere has one possible solution. Usually , this is enough to set me on the right track.

philonoist 8y ago

Solutions were stepping stones to my success. I am mature enough to not be tempted without trying out the problem. I sleep over it and then at last looking at the solution, if I ever find myself at my wit's end. That is because I have a firm understanding that there is no shortcuts to success. Having come from a third world country where cheating on oneself is delaying even the basic resources to get a job, I was raised with peers finding the 'peeping at solutions' an abhorrent act. Its a big shameful thing to do in my culture. Solutions are the way I learn the thought process of author if he arrived at the final answer in a better way. Solutions expose errors in questions. Errors and typos in Indian texts were way more a common place in questions than in solutions. There was simply not a chance for a solution to have typo or logical errors. If there are no solutions, I'd simply put it for later until I am proficient in the subject and want to try out the problems with confidence. There is always this insecurity when it comes to dealing with logic. Little things can slip in abstract thinking pretty easily. Silly mistakes take a toll. People like myself prefer to solve problems individually at our own pace. Solutions are a must for me. Of course, that 'later' almost always never comes.

jefferickson 8y ago

Hi, I'm the author. I'm honestly seriously torn about this. There is a serious tension between pedagogical needs of students in formal classrooms and the pedagogical needs of self-learners. I've chosen to aim for the former. Yes, I know it's a bummer. (From experience) providing solutions interferes with the learning process of my own students at Illinois. I have to change up homeworks and exam questions every semester, because otherwise students will look up and copy/memorize the answers instead of trying to figuring them out, which means they do worse on the exams where they HAVE to figure things out. Also, a significant majority of the requests I get for solutions are from university students who want to cheat. I do provide solutions to the homework and exam and lab problems I assign in any particular class, after the fact. (And I release those solutions publicly, despite the protests of colleagues at other universities, until the semester ends.) And I have started proving model solutions in the homeworks, so that the students know what kind of answers I'm looking for. (See the course materials page, under CS 374.) In practice, my stance is becoming increasingly moot, as more of my official solutions get uploaded to places like CourseHero and Koofers and their many foreign-language equivalents. I am very likely to include solutions for a subset of problems (maybe three or four per chapter) in a future edition. But that will take a significant amount of time, and I wanted to get something out the door.

smarks 8y ago
Thanks for this explanation. This is one of the things that popped out at me when I looked at the book page. The statement about not providing answers seemed quite dogmatic, and my initial reaction was, why? Turns out it's not so dogmatic, and there's a thoughtful and nuanced explanation. Perhaps you could include some of this on the book page, or provide a link to the explanation elsewhere.
- _underflow_ 8y ago
  Completely agree - being outside academia has apparently made me ignorant to a lot of the pitfalls to actually posting said solutions. Makes perfect sense when put this way. I also really appreciate the response from the author. I forget the gurus behind books like this often have a presence here on HN.

commandlinefan 8y ago

> I like to be able to check my answers when teaching myself things. I agree, although looking at the exercises in this book, they seem to be of the form where the only way to give you the answer is you give you the full solution, and they appear to be phrased in a way that makes it easy enough to verify the answer yourself once you’ve figured out the problem. I always feel like the ideal (for me at least) are problems with numerical answers listed in the back of the book – then I can check my answer with the book’s answer; if I got 42 but they got 5, I know I made a mistake somewhere but it’s still up to me to go back through and figure out where the mistake was. It seems like most of these problems don’t lend themselves to short numerical answers like that.