Results tagged “puzzle” from kwc blog

The following short quiz consists of 4 questions and will tell you whether you are qualified to be a professional. The questions are NOT that difficult. [Ed: the answers are in the extended. It's best if you read the answer to each question before proceeding to the next]

1) How do you put a giraffe into a refrigerator?

2) How do you put an elephant into a refrigerator?

3) The Lion King is hosting an animal conference. All the animals attend.... except one. Which animal does not attend?

4) There is a river you must cross but it is used by crocodiles, and you do not have a boat. How do you manage it?

reformatted from Jeremy Zawodny's blog (I had trouble not reading the answers with the question).

Puzzle: Horsies

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I feel in a puzzle-giving mood, so here's one that rcp will recognize this from her Oracle interview:

There are 25 horses, and you can race 5 of them at a time. Strangely, you have no stopwatch, but the horses always run exactly the same in every race. How many races does it take to figure out:
* the fastest horse?
* the top three fastest?

Answer to Coin Puzzle

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For those stumped or wanting to check their answers, read on to see the solution to Friday's coin puzzle.

Coin puzzle

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Here's a puzzle to waste your weekend on. Got it from toons.

Professor S.F. Mann has just returned home, surprisingly unscathed, from a lecture in New Haven. He realizes that he has collected 100 Sacagawea dollars in change from the train ticket vending machines. He tells his kids Billy and Mary that he'll split some of the coins with them. He goes in to his dark room alone and places the coins on a table with 60 of them heads-up. S.F. then tells Billy that he must arrange the coins into two piles without the aid of any light. Afterwards Mary will be allowed to choose which pile is hers and which is Billy's. The children will then receive all of the Sacagawea coins that are heads-up in their respective piles, and S.F. will take the remaining coins. Billy hates losing to Mary and so his goal is to divide the coins up so that each pile contains the same number of heads. He is allowed to shuffle and flip the coins whichever way he wants, but he cannot tell which side is heads up while he is putting them into two piles (the room is dark, and Billy's sense of touch is a bit dim too). What should he do?

I'll post an answer next week, but for now I will state the following:
- Billy cannot stand the coins on edge
- Billy cannot walk away with any coins
- The solution for this problem works all of the time (i.e. the solution does not rely on probability over time)

Crossword oops

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I found this browsing through a comment thread about the 'controversy' brewing over the fact that the winning word for this year's Spelling Bee, 'autochthonous', was also Dictionary.com's word of the day the day before.

While people can debate the probability of that being a coincidence, someone else posted an article about a 'coincidence' dating back, appropriately enough, to D-Day. The code names for for the highly secretive D-Day plan -- Utah, Omaha, Overlord, Mulberry, Neptune -- started appearing in the Daily Telegraph crossword puzzle in the weeks prior to the invasion.

Telegraph | News | D-Day crosswords are still a few clues short of a solution

Book: How Would You Move Mount Fuji

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This book is targeted at people who are preparing for an interview. Although it is a book about interview puzzles, the puzzles take up very little of the book. Most of the book is dedicated to interview guides (for the interviewer and interviewee) and the history of the logic puzzle, from its use in IQ tests to its adoption by job interviews. The history was a little bit interesting to me, mostly because it talked about Shockley, and it also happened to mention Jim Gibbons name, which made my world a little bit smaller. The main reason I picked this book up, though, is that I happen to like the puzzles that they give you during interviews, and I'm too lazy to find them on the Internet.

There are plenty of Fermi estimation questions in the book (the title of the book ends up being one). Fermi estimation questions ask you to estimate the value of something you don't know, like the number of redheads in Ireland. When I was in high school, we had an entire unit on this in chemistry. My chemistry teacher introduced the unit by telling the anecdote of Fermi at one of the nuclear bomb tests. As the shockwave approached, Fermi threw some scraps of paper into the air and watched their deflection. From this observation, he came up with an estimate of the megatons of the explosion that was reasonably accurate.

It's really not much use searching for examples of Fermi type problems; pretty much any type of estimation will serve as practice. Although it's nice to have estimation skills, as puzzles I find these a bit boring.

Another class of problems they have are design-type questions, where you get asked how you would design/build some sort of item. While I think these are good interview questions, as they allow the interviewer and interviewee to interact back and forth, I don't find them too interesting to solve in my freetime.

The last class of problems, logic problems with actual solutions, are the ones that I was shooting for when I got the book. There are some good ones in this book which made it worth the price of admission. Here are some of my favorites:
- 5 pirates have 100 gold coins to divide. The senior pirate proposes how to divide the coins, and the pirates then get to vote. If at least half of the pirates agree to the proposal, the division is made; otherwise the senior pirate is killed and the process is repeated. If you are the senior pirate (pirate #5), what should you propose?

- There is a village of 50 husband and wife couples. All of the husbands have been unfaithful. The wives know when men other than their own husbands have cheated, but they don't know about their own husbands fidelity. If a wife can prove that her husband has cheated, then she is required by law to kill him. Also, all of the wives are blessed with Spock-like logic skills. One day, the queen stops by and announces, "at least one of your husbands has been unfaithful." What happens?

- How many points are there on the globe where, by walking one mile south, one mile east, and one mile north, you reach the place where you started?

- Count in base negative 2 (doesn't have a "correct" solution)

- You have five jars of pills. Normal pills weight 10 grams, while poisonous pills weight 9 grams. One of the jars is filled with poisonous pills. Measuring once on a scale, how do you find the poison jar?

Puzzle: The Game: Buffyphilia

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Original puzzle:
BUFFYPHILIA

Buffyphilia solved (well, almost):
"HUNDRED SEAPORT BLVD REDWOOD CITY"
One word unsolved: "TEN EFFS" or "STEFFEN"
(the 'S' should have been an 'I', giving FIFTEEN)

Description of puzzle: seven pages of screen captures of Buffy and Gilmore Girl episodes. On each page the screen captures are arranged in a cross. The first page serves as a link to each of the other pages. On the other pages, it is noticeable that the sizes of the images don't line up perfectly, this turns out to be the key to the puzzle (it turns out that the names of the episodes is not meaningful). The other key to the puzzle is to ignore Gilmore Girl episodes. The baseline dimension of the images is 240x180. The encoded character is determined by the offset from that size, so 241x180 = A, as does 240x181.

X - Gilmore Girls episode, ignore

Index 0: establishes baseline for character decoding
240 180
240 180
240 180
240 180
240 180
240 180

Index 1
BLVD (If you include Gilmore Girls, you get BEDEVIL, clever)
244 180 D
240 182 B
240 202 V
252 180 L
X 240 185 E
X 245 180 E
X 249 180 I

Index 2
FIFTEEN (originally decoded wrong as TEN EFFS/STEFFEN)
240 185 E
240 186 F
240 186 F
240 185 E
260 180 T
254 180 N
249 180 S (This should be an 'I')

Index 3
CITY
240 183 C
240 200 T
249 180 I
265 180 Y
x 248 180 H
x 240 199 S
x 258 180 R

Index 4
HUNDRED
254 180 N
240 185 E
240 184 D
240 188 H
261 180 U
258 180 R
244 180 D

Index 5
SEAPORT
260 180 T
240 181 A
240 185 E
240 196 P
258 180 R
255 180 O
259 180 S

Index 6
REDWOOD
258 180 R
240 195 O
240 195 O
240 184 D
263 180 W
244 180 D
245 180 E