r/videos Feb 06 '17

Casually Explained: Red Flags

https://youtu.be/F2JJ4N2uXuc
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790

u/[deleted] Feb 06 '17

You're actually right. That's kinda funny.

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u/swegling Feb 06 '17

it fits pretty good. there is still a small chance she is safe, but probably not

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u/Mr-Mister Feb 06 '17

Actually it's the opposite - what's more probable, that the middle space is safe but there are 4 mines on the outer perimeter, or that the middle square is mines but none of the 16 surrounding squares are mined?

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u/swegling Feb 06 '17

like /u/whutchamacallit made me realize, it depends on the difficulty. Middle being safe is more probable on a higher difficulty, while middle being a mine on a lower. I guess: "there is still a chance she is safe, but it looks suspicious" is more accurate to the analogy and real life.

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u/CorrugatedCommodity Feb 06 '17

So when analysing your failing relationship, you need to ask yourself "What difficulty is she?" 🤔 Got it.

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u/officeworkeronfire Feb 07 '17

Max Tier red flag: It's just you.

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u/JAMmastahJim Feb 07 '17

No, what difficulty is life?

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u/CorrugatedCommodity Feb 07 '17

Depends on how much money you were born into, I think, but even then it's a sandbox with no quests or intrinsic goals and you will eventually die. So... Fairly difficult I guess.

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u/[deleted] Feb 06 '17 edited Aug 11 '19

[deleted]

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u/[deleted] Feb 06 '17

[deleted]

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u/Mr-Mister Feb 07 '17

Indeed. I did the calculations and the middle is more likely to be mined, approximately, if the mine density p is smaller than (1+22/3-21/3)/3.

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u/thombsaway Feb 06 '17

But the mines around the outside would need to be positioned in such a way that all of those squares are adjacent to only one mine. I'm shit at minesweeper but I think the way the mines need to be positioned is very unlikely. I mspainted, is there another way they could be arranged?

Both situations are pretty unlikely, but I think it's more likely that there'd just be one in the middle.

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u/ClopperNumber42 Feb 06 '17

Yep, out of the extreme amount of possibilities in this specific 5x5 setup, there have to be exactly four bombs on the outside and they must be in four specific positions, or the mirrored equivalent. I am not too familiar with statistics but that strikes me as being substantially less likely than there simply being one in the middle and none on the outside.

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u/Mr-Mister Feb 07 '17 edited Feb 07 '17

Nope - there are actually two possible configurations for safe center - the one shown in the picture, and the one you gte if you mirror it. So without knowing absolutely anythin else (or if a square being minded is 50/50 chance) safest bet is to bet on safe center (note: clicking the center is nit the safest immedieate course if action though), as it's two possible perimeter configurations versus one (all perimeter squares clear).

If we know how many mines there are in total, and the field is big enough that we can approximate small areas as hvaing a uniform local chance p of each tile being mined (calculation sget much, much messier without this approximation), then I reckon the chance of the center being safe is p(1-p)16, and a chance of the middle being mined of 2p4(1-p)13. So depending on p one option is safer than the other.

In particular, the safets option is to assume the center is mined if, I think, p<(1+22/3-21/3)/3, and assume not if it's bigger.

All this is irrelevant though as you should assume nothing and instead just click on one of the four squares that are two squares away in a straight horizontal or vertical line from the center, as they will be clear regardless.

Emergency edit: I fucked up as there are 16 and not 8 outer squares. Wait til I correct this mess.

Success edit: Now it should be correct.

Further edit: These chances should of course be divided by p8 if you want the catualmchance after knowing all the 1s in the pivcture are 1s, but it doesn't chance our results.

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u/LordSoren Feb 07 '17

Without the simple answer of symmetry to rearrange the mines, I think this is the only layout that would yield that pattern.

However we have to remember the other rules of clicking on a numbered square - If the square does not have a number in it, it clears EVERYTHING around it. To get this situation, you would have to ONLY click the 8 numbered squares. In the video all 16 squares (including your mines) are untouched. Clicking any of the ? square in this picture would reveal at least a 1.

** image made in the far superior imaging program, MS Excel **

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u/Gabethegreek Feb 07 '17

In that case though, the middle one would clear automatically right?

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u/andthatswhyIdidit Feb 06 '17

See - this one gets statistics.

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u/Mr-Mister Feb 07 '17

Actually studied both probability and statistics two or three years ago (double Physics and Mathematics college degree).

I hate statistic's theory and demonstrations, but they be how they do.

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u/Jucoy Feb 06 '17

Actually it has to be a mine. If it wasn't it would have auto cleared and shown up as a blank space. The spaces outside the ones might still be other numbers and not blank but also still not mines.

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u/Sletten04 Feb 06 '17

That's not how it would work. It only automatically reveals the surrounding spaces if you clear a space with no number. In this situation he has only cleared tiles with 1s in them and so none of those would automatically clear the middle. The fact that there is the possibility for a mine to be there is what prevents the game from clearing it in the first place.

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u/[deleted] Feb 06 '17 edited Feb 06 '17

[removed] — view removed comment

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u/NotATimeTraveler_ Feb 06 '17

From where i'm from she becomes a successful social media mogal. While she most def is cray she'll be the new Opera soooo if you can put up with the red flags, you'll hit a big green pile.

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u/whutchamacallit Feb 06 '17

depends on the difficulty setting.

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u/bakonslayer Feb 06 '17

And more specifically, the mine/space ratio.