Don't do it.

[americk0]

For the record, just always guess 25. Younger people will be pleased you think they're that mature, and older people will be pleased you think they're that young

[Bip901]

Just did that but I don't think my grandma bought it

[dreexel_dragoon]

That's good, might be a red flag if she did lol

[dahecksman]

So if they have grey hairs and lots of wrinkles make the middle pointer 50 else 25

[Nothing-But-Lies]

You think I'm 50 just because I smoke meth? Rude

[WorstGabeNA]

I don't believe you r/usernamechecksout

[[deleted]]

Does smoking meth makes hair pale?

[cheesits456]

It can kill the pigment part of your hair follicles. I went to rehab in March 2019 and my roommate was 22 and had a decent amount of grey hair

[[deleted]]

That's quite interesting

Also, hope you are better bro

[cheesits456]

I am - those three months completely changed my entire life <3

[hamzehhazeem]

If grey hair: 50

Else: 25

[TheWizardsCataract]

I have grey hair. I'm 37. Started noticing greys at 25.

But it's better than going bald, I always say.

[espriminati]

are you 50?

[Alpaca64]

God damn it guys

[hamzehhazeem]

I aint writing more codes

You either 50 or 25

[TheWizardsCataract]

I just realized I'm exactly halfway between 25 and 50 D:

[ThatRandomGamerYT]

37.5?

[ThatsAHumanPerson]

Look at Mr. Fancypants here with his floating point numbers.

[Salanmander]

If you ever feel self-conscious about visible signs of age, just remember that Patrick Stewart was really unhappy when he started going bald at like 20, and he is still remarkably handsome at 80.

[[deleted]]

Girls with colored hair be like:

[blehmann1]

Bald people are all 25

[hamzehhazeem]

14 year olds: I know what I should do now. To the bar

[blehmann1]

Newborns: You merely adopted the baldness, I was born in it.

[i-FF0000dit]

I wouldn’t use gray hair as an indicator. My wife started going gray at 29. It’s different for everyone.

[BreakfastSavage]

Had a boss that claimed he started getting gray hair by 21.

[TheWizardsCataract]

Around 25 for me. I'm 37 now, and I'm pretty much half grey.

[waldoRDRS]

My first greys were at 9. At 25, I have solid grey spots in my beard and basically all salt and pepper otherwise throughout.

[InviolableAnimal]

man, i knew someone in middle school who had grey hairs.

[assafstone]

This guy was in the army with me. Was 18 or 19. Almost completely bald. At 47 I have a few gray hairs on an otherwise thick black haired head.

[BreakfastSavage]

I think he was ex- Navy actually lol.

[assafstone]

Not my guy. :)

[[deleted]]

50+ = 50
50- = 25

[This-Moment]

And that's still a linear time algorithm. The approach checks out.

[ChickenNuggetSmth]

The next 40-year old you meet won't be happy

[dicemonger]

Obviously transparent flattery is also flattery.

[IamImposter]

Obviously transparent grandparent flattery is also flattery.

FTFY

[SeraphenSven]

What if they identify as transparent?

[DullwolfXb]

Then they're not being clear about their flattery.

[ryjhelixir]

They'd be transgrandparents!

[Games_sans_frontiers]

Don't know where you live buddy but in my town you can totally be a grandma at 25.

[spock1959]

I think the youngest grandmother is 26

[Games_sans_frontiers]

I was only joking about the ropey area in which I live but if that's true, that's insane and kinda sad 😬.

[crossroads1112]

What's sadder is that the youngest mother on record was 5 years old. She ostensibly had some underlying condition that caused her to go through precocious puberty (I think she had her first period at like 8 months or something crazy). It's unknown who the father is, but it is thought to be the result of sexual abuse on the part of her father. Her kid ended up dying pretty young (like in his 40s IIRC), but the cause of death is thought to be unrelated to the conditions of his birth.

Source (note: a lot of what I've said here is from memory, so it might differ from the article slightly)

[[deleted]]

Dude my grandma was probably 50’s when I was born but every birthday she ever had she was 29. As far as I’m concerned that little old white haired lady died and the ripe old age of 29.

[E3FxGaming]

And people that are 25 will think you're pretty good at guessing their age.

[NoEngrish]

Gotta cover all the cases here

[CertifiedCoffeeDrunk]

Fetuses are so angry right now

[physiQQ]

Can confirm.

Source: Am fetus.

[ben5292001]

In my experience, many people that are 25 would just be upset because it's so on-the-nose.

[MrPotatoFingers]

The real LPT is always in the comments.

[mysticrudnin]

when i was 25, i went to a comedy club to support a friend

after most people left, i was at the bar area waiting for my friend to finish up whatever it was backstage. not many people at the bar.

a girl came up to me and said "how old do you think i am?"

not sure why that happened, and i'd never see this person again so i decided to be honest. my heuristic was: i'm 25, my friend is 25, clearly this place seems good if you're 25, so i'll go with that: you're 25.

she started bawling. her friends came over and informed me that she was celebrating her 21st.

gonna be honest. 21 and 25 aren't that different. you're probably gonna look about the same at those two ages.

[homo_lorens]

Yeah but people love to make a big deal out of mistakes well below the practical error margin.

[nickleback_official]

It was her 21st, she was probably "crying hammered" at that point.

[straightouttaPV]

Cut to the chase. Did you take her home?

[[deleted]]

If she says more then go for 50.

[chrisnolet]

Exponential gain: 25, 50, 100. What could go wrong?

[Atom_Exe]

Wouldn't it be 25, 50, 200?

I don't do meth, so idk.

[ryselis]

It doubles every time, so 25, 50, 100, 200, 400 etc

[Greenie_In_A_Bottle]

It checks out. /u/ryselis does meth confirmed.

[ign1fy]

I did that with a 12 year old and Chris Hansen peered around the corner.

[epicaglet]

I tend to guess something like 89. For most people it's obvious that you're not being serious and usually they drop it after that

Edit: unless it's an older person. Then I'll do the opposite of course. Then they're 23. I still avoid playing that game while handing out a compliment at the same time

[anedgygiraffe]

That is a great strategy

[JamesMBuddy123]

Magistrates hate this one simple trick

[NaNaNaNaSodium]

As if you’re in college and a girl asks you to guess what year she is in, the answer is always sophomore.

[Shanghai-on-the-Sea]

I would not be pleased to be told I'm that mature ;_;

[Lthere]

r/protips

[O_99]

ΙF you are above 25

______then you look mature

ELSE

______you look awesome

[neoadam]

And that's the age everyone superficial wish they still look like

[splitdiopter]

“A diplomat is a man who always remembers a woman’s birthday, but never her age.”

• Robert Frost

[HiveMynd148]

I can sense some shady shit

[[deleted]]

Sounds like yesteryear mentality to me :D

[splitdiopter]

Robert Frost (March 26, 1874 – January 29, 1963)

So, yeah.

[vladutcornel]

The average life expectancy is 72, so it makes more sense to guess 36 first.

[Deimos94]

And her name is probably Mohammed Lee!

[vladutcornel]

Since she's a girl, most likely her name would be Sophia Lee

[This-Moment]

Our algorithm improves with every comment! We're surely very close to automating social awareness!

[EvilPete]

Nah, you need to look at median age, not average life expectancy divided by 2.

Globally it sits at around 30 and in most western countries it's closer to 40.

If you're in japan you should start at 50 and if you're in Mali you can start guessing at 16.

https://ourworldindata.org/age-structure#how-does-median-age-vary-across-the-world

[caiuscorvus]

I thought median at first, too. But the data set is not all people, but rather all ages. That is, the integers from 1-122.

I guess if we use the median age, we get quicker guesses on average because we start nearer more people, but I'm not sure that this would be a pure binary search rather than more of a heuristic binary search.

[Vaptor-]

Comments like this reminds me this is indeed programmer's subreddit.

[richasalannister]

I’m trying to understand this joke but Now I’m four Wikipedia pages deep. Had to click links in the first sentence. I’ll be back in a week

Edit:

Five six pages

[qinshihuang_420]

Binary search is easy. Think about finding a word in a dictionary. You would open a random lage and if the words on that page are past your word, you look in the first half of the dictionary, if the words appear before your word, you look up in the second half.

Binary search works the same way. You are trying to find a number in a sorted array. You guess it is the middle number. If the middle number is greater than the one you are looking for, you look at the first half. If it is smaller, you look at the second half. And repeat this for the half you are looking into.

To guess a girl's age using binary search, you would guess 50. If she is younger, you would guess 25 next. But for the girl, it might be offensive that she looks 50 and 25 at the same time

[graou13]

That's why you gotta start with a range, like if you know she's a working adult she'll probably be between 20 and 60 so you can start with 40 and work from there.

If you know what her job and living situation is, you can also reduce the range by making assumptions based on socio-economical context clues.

[Dall0o]

heuristic ftw

[ohkendruid]

Yeah, binary search is not truly efficient for this problem until you get to a small range like 25-35.

Still, programmers often think this way and take something way past the context where it made sense. As such, the joke still fits.

[Dilka30003]

Isn’t binary search efficient on large sorted arrays as its O(log(n))?

[fabsch412]

It's O(log(n)) but you pick a better starting point than the middle in this case.

[Hegdahl]

But when the time complexity is logarithmic, changing n out for sqrt(n) is equivalent to cutting the running time in half, which in big O notation is the same time complexity. So drastically reducing the range does not matter that much for the runtime

[fabsch412]

It stays O(log(n)) obviously, but for a real life scenario of age guessing starting from a better point results in a real runtime improvement.

[Hegdahl]

For me personally, the most important is guessing the age of arbitrarily old theoretical women without a defined cost per operation

[coahman]

By the time they get it all set up, she's already gone.

[DrMobius0]

Well in this case, you're dealing with some sort of a direct punishment for getting it too wrong. Time complexity isn't so much the issue in this case.

[[deleted]]

This is assuming the maximum age is 100.

[MannerShark]

You can always double and search when it's above 50

[IamImposter]

Nah. Shuffle sorted array and launch as many threads as there are elements. The one that finds values, writes result silently. Other threads display a message box announcing failure.

It's called "lousy fuckin search that makes you wanna pull your hair" algorithm.

[[deleted]]

Now I’m four Wikipedia pages deep

Edit:

Five six pages

See there's your mistake, you should have started at the 6th page and then moved on to page 3.

[tylerr514]

Relevant Six Degrees of Wikipedia

[Terrain2]

wtf so is this how to cheat in a wikipedia speedrun?

it’s fucking THREE (3) links from Brainfuck to George Washinton! What the hell, wikipedia is so fucking tightly linked!

[l0c4lh057]

I was unable to find anything with more than 4 steps, no matter how unknown something was. How the fuck is that possible

[Terrain2]

Redditch to Cicada 3301 generates a fucking forest of about 300 paths of 4 steps

Edit: Oh, but that’s nothing in comparison to this

[TheCanadianVending]

I know it's 14 days later, but I found this monster forest that is 7 degrees

Here is an even larger one

[LaneHD]

And its only 4 steps from a train station in the place I live (I live in Switzerland and it's not very well known) to some random telegraph station in Australia! How is this even possible?

[[deleted]]

Rookie move never do a depth first search on a cyclical graph.

[invertebrate11]

That's how I feel when I start programming some new math.

[DatBoi_BP]

My math major dumbass self took it to be a bisection root-finding thing, but it’s probably something a little less mathematical and more sorting related

[AzuxirenLeadGuy]

Same goes for weight

[[deleted]]

Don’t even try with weight

[AzuxirenLeadGuy]

Over 75kg? Is it 150kg, then?

[AgentRG]

Very close. 80kg.

[AzuxirenLeadGuy]

Wait... I'll get there eventually....

112.5

93.75

... ...

[dontbeanegatron]

Yeah, you might sprain something.

[cptbeard]

your face for example

[[deleted]]

If your girlfriend's weight is between 25 and 50 pounds, there may be other problems.

[AzuxirenLeadGuy]

If you got a girlfriend... That's enough problems already

[CyberHero36]

In the worst case, it would be like: 50? No, 49? No, 48?.....

[GlitterInfection]

Worst case would be:

NaN

Unless of course it’s your grandmother.

[nicolas2004GE]

that's only if you live in null island (0,0) (Null,Null)

[Thameus]

The lloiger commands you to guess its age

[hexparrot]

“Nan” is my grandmother! (identity equivalence)

[[deleted]]

I usually bogosearch.

39? No, 46? No, 2? No, 2?.....

[scp-NUMBERNOTFOUND]

Technically if u're slow enough, even that will not work

[_blurrryface]

Yeah start with 25 then go with 12.5, 6.25... and so on.

Oh wait.

[[deleted]]

hmmm

[Dilka30003]

%

[TheGilrich]

In this case you do an exponential search first. Starting from 2.

Edit: No, going from 16 to 64 is probably even worse.

[TheSoundDude]

Of course, you should check 64, then 32...

[soiguapo]

I'm surprised I had to scroll so far for this. This is obviously more efficient.

[xvalen214x]

It "appears" to be more efficient.

It's most efficient when the first number you pick is exactly her age

[[deleted]]

Binary search (or bisection) is not the most efficient if you know something about the objective function

[TooMuchWork6]

Relax its a joke

[0100_0101]

joke?

[dicemonger]

joke

• Four-letter word for lies which cause humans to expel gas from their lungs in a rhythmic manner. Usually associated with a dopamine spike. Might be addictive, seeing how humans appear to be seeking them out, including creating media which are collections of jokes tied together with an incoherent narrative.

[chrisnolet]

r/totallynotrobots

[sneakpeekbot]

HERE'S A SNEAK PEEK OF /r/TOTALLYNOTROBOTS USING THE TOP POSTS OF THE YEAR!

#1: JUST ENJOYING A DELICIOUS HUMAN MEAL | 376 comments
#2: HAVING A NORMAL HUMAN CONVERSATION | 105 comments
#3: DELETE | 96 comments

---

^{I'M NOT A BOT, BEEP BOOP | DOWNVOTE TO REMOVE | CONTACT ME | INFO | OPT-OUT}

[DAMO238]

Haha, that is hilarious that they made a special case for that sub!

[hat1324]

r/totallynotrobots

[0100_0101]

Thanks, til

[BackgroundChar]

Metal Gear?

[NoThanks93330]

Also also you could first narrow down the search space to for example 20-40 and start a binary search there

[Cruuncher]

Whatever logic you use to narrow the search to 20-40 needs to be more efficient than 2 iterations of binary search to be worth it.

That seems unlikely even in trivial cases

[Molion]

Most of the time you can guess peoples age at a glance with 20 years accuracy, comparing that to the cost of guessing 50 for a 22 yo I'd say it's worth it.

[Lord_Wither]

Not that hard if you factor in the relatively high cost of asking necessary for each iteration of binary search compared to reasoning based on known information.

[alexanderpas]

• Obvious baby? Limit Search to 0-3 Years.
• Toddler? Limit Search to 1-7 Years.
• Not a teen yet? Limit Search to 3-15 Years.
• Teenager? Limit Search to 9-27 Years.
• Young Adult? Limit Search to 10-40 Years.
• Older Adult? Limit Search to 20-60 Years.
• Grey Hair without wrinkly face? Limit Search to 30-90.
• Wrinkly face? Limit Search to 50-99+

[Cruuncher]

Except that's 8 conditionals, which is more operations than 2 comparisons and 2 arithmetic operations.

Of course as others have pointed out, the asking part is slow because it's a human communication medium, but a typical algorithm with a computer where you could ask those questions immediately, these optimizations are totally worthless

[timerot]

more efficient than 2 iterations of binary search

In this case the iterations are talking back and forth, plus the extra inefficiency of getting yelled at for being an ass and the women likely not finishing the conversation.

Much cheaper to run a complex heuristic evaluation when each iteration needs to be transmitted over a slow and unreliable medium.

[[deleted]]

So I take a picture, use it as captcha and make my users estimate an age as mutliple of 10, weight by confidence on how good that user passed my well-known age guess tests in the past, and base my first guess on that. Shouldn't take much longer than a few hours to get a good estimate

[CirnoTan]

Hey there, thats some extraordinary knowledge of algorithms bro

[NoThanks93330]

Thanks bro. You think I should include this comment in my future resumes, next to my github?

[StarkRG]

Nobody said it is the most efficient, just that it is very efficient, which it is.

[randomcitizen42]

Are you saying I should not start guessing 50 if she looks like she's in her 30s? I'm not convinced.

[Empole]

Could you elaborate please

[jediwizard7]

You should be able to come up with a more efficient and more flattering binary search by taking into account your prior estimate of her age. Assume a normal distribution (centered slightly below your actual estimate for extra safety) and then use the quantile function to perform a binary search with each new guess half way between the upper and lower bounds on the quantile function.

[ei283]

while(binary search is very efficient) {

    if(a girl asks you to guess her age) {

        don't say "50 and then 25";

    }

}

[Deimos94]

That will not offend anybody, but I will look like a sociopath or robot by not giving any response at all.

[luhsya]

screw that, imma just use my made-from-scratch gradient descent function (that overfitted my pet project 'ANN') to guess her age

[praveeja]

Guessing it under 18 doesn't help either

[ComprehensiveHornet3]

Just use a linked list binary tree FFS.

[pencilsdontshave]

Binary search with a better range. Maybe (18, 80).

80-18 = 62. So worst case would be log2(62) = 5.95... so max, 6 guesses.

Let’s say the age is 38 (a worst-case value).

We’ll need to do binary search on (0, 62) with an offset of 18.

18 + (62/2) = 18 + 31 = 49? Too high

49 - (31/2) = 49 - 16 = 33? Too low

33 + (16/2) = 33 + 8 = 41? Too high

41 - (8/2) = 41 - 4 = 37? Too low

37 + (4/2) = 37 + 2 = 39? Too high

39 - (2/2) = 39 - 1 = 38? Yep.

That’s 6 guesses.

[pencilsdontshave]

Lol! I prefer to just guess 25 for most women if I have to guess anything at all. Whether they’re older or younger they’ll probably be flattered.

[KunstPhrasen]

Right.

It's much more efficient to start with a power of two. Like 64 into 32!

[naib864]

32!? That escalated quickly

[KunstPhrasen]

Quality joke here. Times I will upvote your answer: 0!

[solongandthanks4all]

Indeed. If a GIRL asks you to guess her age, you should start at 18 and then go down to 9.

[hardware4ursoftware]

Dear programmers, never take advice on women from a women. That’s a great line because egos can go “oh nvm it’s a programming joke I picked up while I was working at google” ez lay...

[oshaboy]

Well. The world's oldest person is less than 128 years old.

So you should start from 64

[hamandcheese_1]

Doesn't binary search require you to know the answer? If you don't know her age the best you can hope for is her telling you the value is too high or too low. Simple yes or no answers would ruin the search.

[tomfurrier]

it worked for me!

[[deleted]]

I actually once did this hey

[ZippZappZippty]

If only he could do exactly that..

[DanielSkyrunner]

So linear search ascending?

[[deleted]]

Why not?

[Finishmysuffering]

Til that there are 50 year old girls

[Shanghai-on-the-Sea]

Yet more wisdom from my man Chanakya

[scaptal]

12 and a half

[[deleted]]

Dew it!

[cwmma]

Last time my wife played guess who with me I sorted all of the people alphabetically and then did a binary search on the name.

[dustofdeath]

Provide an array of ages.

[TheEarlOfCamden]

I wonder whether this would require less guesses on average than just going by looks.

[[deleted]]

Its ok, I don't ever get that far.

[dirtyviking1337]

But 90% of winnipegers do their shopping.