A Quick Puzzle to Test Your Problem Solving • Hacker News Board

Re: A Quick Puzzle to Test Your Problem Solving

#141

Post by tikhonj » Thu, Jul 02, 2015, 6:09 PM UTC

veli_joza wrote: post #10

ddlatham wrote: post #3

I'm curious to see more about the distribution of questions and answers people had, and how the HN population may differ from the NYT's. There will certainly be self selection bias here, but if you're willing to share how you did with others, please enter it here: https://docs.google.com/forms/d/17e5BIL0lH8OHsGj89Zdtdl8GeCV... The result summary is visible here: https://docs.google.com/forms/d/17e5BIL0lH8OHsGj89Zdtdl…

People familiar with unit testing and test driven development will feel at home with this kind of puzzle. That doesn't mean that they will be less biased in social/political decisions, it just means that this test will fail to prove a point.

I mean, it also illustrates how training and systematic reasoning can improve these things. Whether explicitly or implicitly, I picked up certain skills and procedures for problem solving (from programming and math contests) that I now use by default. Trying a bunch of examples, coming up with a hypothesis, trying to disprove it, testing edge cases…

This doesn't mean I always use these—at the very least, I have to explicitly jump into "problem solving" mode—but it means they can be useful.

It's still a meaningful difference, and could very well apply to lots of things beyond this kind of puzzle.

Re: A Quick Puzzle to Test Your Problem Solving

#142

Post by rahimnathwani » Thu, Jul 02, 2015, 6:10 PM UTC

diminishedprime wrote: post #59

veli_joza wrote: post #10

Earlier quoted context omitted.

People familiar with unit testing and test driven development will feel at home with this kind of puzzle. That doesn't mean that they will be less biased in social/political decisions, it just means that this test will fail to prove a point.

That's exactly what I was thinking. I (sometimes) follow TDD, and I applied it to this problem. I made sure to include negatives, 0, positives, and include primes here or there to help avoid issues with multiplication/exponentiation. After a few of these, I felt pretty confident that the rule was simple.

I was a little less systematic, but still had a positive:negative ratio of 1:2 before I submitted my answer.

4,6,8 Y 1,1,1 N 1,2,3 Y 1,6666,8777 Y 1,0,1 N 3,2,1 N 3,2,3 N 5,6,4 N 7,5,6 N

Re: A Quick Puzzle to Test Your Problem Solving

#143

Post by damoncali » Thu, Jul 02, 2015, 6:10 PM UTC

Cool. The funny thing is I inserted a constraint of my own invention without even realizing it: "Use the fewest number of examples possible." Of course, this meant failing miserably, and was nowhere in the problem statement.

Perhaps that's an additional factor - not exactly confirmation bias, but not unrelated.

Re: A Quick Puzzle to Test Your Problem Solving

#144

Post by thekingofspain » Thu, Jul 02, 2015, 6:12 PM UTC

stillsut wrote: post #108

cabirum wrote: post #23

function judgeSentence(sentence, numNo) var probablyWrong = ["doubl", "expon", "multipl", "^", " ", "power", "two", "2", "twice", "as big", "nth", "rais"]; var seemsRight = ["larger", "increas", "greater", "small", "less", "big", ">", " Been expecting something more interesting than that

include "monoton" in probablyWrong. The sequence is not monotonically increasing.

Interestingly, it would appear that monotonically increasing in general means "strictly increasing": http://mathworld.wolfram.com/MonotoneIncreasing.htm

It only means non-decreasing in the context of a monotonic function, where the definition, I believe, is that the derivative of the function is never <0.

Re: A Quick Puzzle to Test Your Problem Solving

#145

Post by aaronbrethorst » Thu, Jul 02, 2015, 6:13 PM UTC

More or less related: when I'm looking for constructive criticism from someone, I'll ask them "what do you dislike about this?" or "what's wrong with this?" instead of "what do you think?"

I tend to get much more interesting and useful feedback this way.

Re: A Quick Puzzle to Test Your Problem Solving

#146

Post by gesman » Thu, Jul 02, 2015, 6:13 PM UTC

After total of 13 answers including 6 "no", I guessed it right :)

Re: A Quick Puzzle to Test Your Problem Solving

#147

Post by MalcolmPF » Thu, Jul 02, 2015, 6:17 PM UTC

yequalsx wrote: post #136

Math person here. I'm curious to know if anyone used decimal numbers in their tests and if negative numbers were used. The rule is increasing real numbers and one can guess that the rule is increasing numbers without realizing this includes all real numbers and not just integers. In addition to getting it right did you use an exhaustive set of tests?

I tried a negative series and a decimal series, just in case the rule was increasing natural numbers. I tried very large numbers to see if there was a limit to the rule, and a series that had large contrast in between each element. For fun I tried to see if the app would recognize "pi", "i", or "e", but, perhaps unsurprisingly, it did not.

Re: A Quick Puzzle to Test Your Problem Solving

#148

Post by crgt » Thu, Jul 02, 2015, 6:19 PM UTC

Retra wrote: post #73

noreasonw wrote: post #70

I think that the "quick" adjective in the title is purposeful misleading. You are supposed to learn quickly the most general rule, but that is not so easy because there are many possible rules that could fit such a pattern. It seems that you should be rewarded for solving the puzzle quickly and then you fall in the trap. I propose to change the title to "A puzzle to test your Generalization Abilities", and state clea…

Maybe it should be "a puzzle many people already know the answer to" in which case the conclusion and results are already obviously biased. I was able to solve the puzzle without testing any numbers at all. Which really skews the relevance of "only nine percent of people saw three 'no's before answering."

You mean you correctly guessed without testing at all - and got lucky. I'm not sure this is the same thing as 'solving' it.

Re: A Quick Puzzle to Test Your Problem Solving

#149

Post by Infernal » Thu, Jul 02, 2015, 6:22 PM UTC

yequalsx wrote: post #136

Math person here. I'm curious to know if anyone used decimal numbers in their tests and if negative numbers were used. The rule is increasing real numbers and one can guess that the rule is increasing numbers without realizing this includes all real numbers and not just integers. In addition to getting it right did you use an exhaustive set of tests?

I did test with negatives, but I did not think to test with decimals. 15 yes's, 6 no's, and I successfully determined the rule.

Re: A Quick Puzzle to Test Your Problem Solving

#150

Post by david_shaw » Thu, Jul 02, 2015, 6:23 PM UTC

stygiansonic wrote: post #42

Neat - as others have pointed out, I feel that being familiar with unit testing would help in this situation. Having negative test cases is just as important, if not moreso, than having "happy path" tests.

That's a great point. Perhaps we should show something like this to new developers who don't understand the value.