The more puzzles, the better! ! ! ! ! ! ! ! ! ! ! Urgent! ! ! ! ! ! ! ! ! ! ! ! ! ! !

1, you let the workers work for you for 7 days, and the workers' remuneration is a gold bar. The gold bar is divided into seven connected parts.

At the end of each day, you must give them a gold bar. If you are only allowed to break the gold bar twice, how can I give it to you?

Workers' wages?

Please cut a box of cake into 8 parts and give it to 8 people, but there must be another part in the cake box.

Xiao Ming's family crossed a bridge, and it was dark when crossing it, so there must be a light. Now it takes 1 second for Xiaoming to cross the bridge.

Xiao Ming's brother needs 3 seconds, Xiao Ming's father needs 6 seconds, Xiao Ming's mother needs 8 seconds, and Xiao Ming's grandfather needs 12 seconds. each

This bridge can be crossed by two people at most. The speed of crossing the bridge depends on the slowest one. After 30 seconds, the light will be on.

Put out. Q: How did Xiao Ming's family cross the bridge?

4. A group of people have a dance, each wearing a hat. There are at least two kinds of hats, black and white.

There is one. Everyone can see the color of other people's hats, but not their own. The host will show you first.

Look at what hats others are wearing, and then turn off the lights. If someone thinks he is wearing a black hat, call himself.

Got a slap. The first time I turned off the lights, there was no sound. Then turn on the light and watch it again. The light is off, and it's still a crow.

The birds are silent. I didn't get a slap in the face until I turned off the light for the third time. Ask how many people wear black.

Hat?

Please estimate the quality of Canadian National TV Tower.

6. There is a diamond at the elevator door on each floor from the first floor to the tenth floor. Diamonds come in different sizes. You take the elevator.

From the first floor to the tenth floor, the elevator doors on each floor will open once, and diamonds can only be brought once. How can we get the maximum benefit?

The big one?

7. The 7.U2 Choir will arrive at the concert venue within 17 minutes, and it will cross a bridge on the way, and four people will walk across it.

You must help them get to the other end. It was dark and they only had one flashlight. one

At the same time, at most two people can cross the bridge together, and they must hold a flashlight when crossing the bridge, so someone has to put it.

Bring the flashlight back and forth to both ends of the bridge. You can't send out the flashlight if you throw it away. Four-person walk

The speed is different. If two people walk together, the slower speed shall prevail. Bono needs 1 minute to cross the bridge, and Edge needs 1 minute.

It takes 2 minutes to cross the bridge, 5 minutes for Adam and 10 minutes for Larry. 17 minutes. How did they do it?

How about crossing the bridge?

It takes an hour to burn an uneven rope. How to judge half an hour with it?

9. Why is the cover of the sewer round?

10. How many gas stations (cars) are there in the United States?

1 1, there are 7 grams, 2 grams of weights and a balance. How to add salt140g to these items for three times?

Divide it into 50 grams and 90 grams each?

12, there is a train from L.A. to new york, with a speed of 15 km/h, and another train comes first.

It's 20 kilometers per hour from new york to LA. If there is a bird, the speed of 30 kilometers per hour is the same as that of the bird.

Two trains are leaving now, starting from Los Angeles, hitting another carriage and returning, flying back and forth in turn.

Ok, the two trains meet on the straight road. How long did the bird fly?

13, you have two cans, 50 red marbles and 50 blue marbles. Just pick one. Just pick one.

Choose a pinball and put it in the bottle. How to give red pinball the best choice? In your plan, get

What is the exact probability of the red ball?

14. Imagine you are in front of the mirror. Excuse me, why can the image in the mirror be reversed from left to right but not from right?

Up and down?

15, you have a can of pills for four people, each pill has a certain weight, and the contaminated pills are not covered.

The pollution weight is+1. Only once, how to tell which can of medicine is contaminated?

16, if you have unlimited water, a 3-quart bucket and a 5-quart bucket, how can you accurately weigh it out?

Four quarts of dehydration?

17, you have a bucket of jelly, yellow, green and red. Close your eyes and choose the same color.

Two, grab two of the same color. You can make sure that you have two fruits of the same color by how much you catch.

Frozen?

18, insert the car key into the door, which direction can you turn to unlock the car?

19. If you could remove any of the 50 states, which one would you remove and why?

20. With all switches turned on, perform the following operations on a batch of lamps numbered 1~ 100.

For all multiples of 1, dial the multiple of switch 2 once in the opposite direction and the multiple of switch 3 once in the opposite direction.

Turn the switch again.

Ask for the number of the light that was last turned off.

2 1, suppose a CD rotates like a turntable on a record player. This disc is half black and half white.

. Suppose you have an unlimited number of color sensors. To determine the direction of rotation of a disk, you need to be around it.

How many color sensors are placed around? Where should they be put?

22. Suppose the clock arrives at 12. Please note that the hour hand and minute hand overlap. Day, hour hand and minute.

How many times do the stitches overlap? Do you know the exact time when they overlap?

23. Two odd numbers separated by a number are called odd pairs, such as 17 and 19. Prove that odd numbers are correct

The number between can always be divisible by 6 (assuming that both odd numbers are greater than 6). Now it is proved that it is not composed of three odd numbers.

Odd pairs.

24. A room has a door (the door is closed) and Three Lamps District. There are three switches outside the house, which are related to this.

Three Lamps District is connected. You can manipulate these switches at will, but once you open the door, you can't change the switches.

Determine which light each switch controls.

Suppose you have eight balls, one of which is slightly heavier, but the only way to find this ball is to put it.

Two balls are put on the balance for comparison. How many times do I have to weigh it before I can find this heavier ball?

26. Let's play a word-splitting game. All the letters are out of order. You have to judge what this word is.

. Suppose this disassembled word consists of five letters:

1.*** How many possible combinations are there?

2. What if we know which five letters it is?

3. Find a way to solve this problem.

27. Four women want to cross the bridge. They are all standing on one side of the bridge, and they should all be in 17 minutes.

Tie the bridge. It's night. They only have one flashlight. Up to two people can cross the bridge at the same time.

Whoever crosses the bridge, whether one or two people, must bring a flashlight. The flashlight must come.

Pass it around. Can't throw it. Every woman crosses the bridge at a different speed. Two people must cross the bridge at a slower speed.

Cross the bridge quickly.

The first woman: it takes 1 minute to cross the bridge;

The second woman: it takes 2 minutes to cross the bridge;

The third woman: it takes 5 minutes to cross the bridge;

Fourth woman: It takes 10 minutes to cross the bridge.

For example, if the first woman and the fourth woman cross the bridge first, 10 will have passed by the time they cross the bridge.

Minutes. If the fourth woman sends the flashlight back, she will always use it when she reaches the other end of the bridge.

After 20 minutes, the operation failed. How to get these four women to cross the bridge in 17 minutes? What other parties are there?

Law?

28. If you have two buckets, one is full of red paint and the other is full of blue paint. you

Scoop a cup from the blue paint bucket, pour it into the red paint bucket, and then scoop a cup from the red paint bucket and pour it into the blue paint bucket.

. Which is the higher proportion of two barrels of red and blue pigments? Prove this by arithmetic.

Crazy calculation

29. Given two numbers between 1 and 30, A knows the sum of these two numbers and B knows the product of these two numbers.

A asks B, "Do you know which two numbers are?" B said, "I don't know";

B asks A, "Do you know which two numbers are?" A said "I don't know";

So, B said, "Then I know";

Then a also said, "then I know";

What are these two numbers?

30, 4, 4, 10, 10, addition, subtraction, multiplication and division, how to calculate 24 points?

3 1、 1000! How many? Why?

32、F(n)= 1n & gt； 8n & lt； 12

f(n)= 2n & lt； 2

F(n)=3 n=6

F(n)= 4n = other

Use+-*/and sign(n) functions to combine the F(n) function.

sign(n)=0 n=0

sign(n)=- 1n & lt； 0

sign(n)= 1n & gt； 0

Write a program to find the sum of prime numbers, such as f (7) =1+3+5+7+113+17 = 58.

34、。 .。

Please use only one stroke and four straight lines to connect all the points in Figure 9.

35. How many kinds of three-level and four-level binary trees are there?

36, 1- 100000 series are arranged in a certain order, and one number is wrong. How to correct it? Write best.

Method. What about two numbers?

37. What is the difference between a linked table and an array?

38. Why do you choose this method to make a linked list?

39. Choose an algorithm to organize a linked list. Why did you choose this method? Use immediately

It's time to do it.

40. Talk about the advantages and disadvantages of various stock classification algorithms.

4 1, use the algorithm to reverse the order of the linked list. Now do it again without recursion.

42. Insert a node into the circular linked list with an algorithm, but it is not allowed to cross the linked list.

43. Organize arrays with algorithms. Why did you choose this method?

44. Use algorithms to match ordinary strings.

45. Invert strings to optimize speed and space.

46. Reverse the word order of a sentence, such as changing "my name is Chris" to "Chris calls me".

It has the fastest speed and the least movement.

47. Find a substring to optimize speed and space.

48. Compare two strings and use O(n) time and constant space.

49, suppose you have an array of 100 1 integers, these integers are arbitrarily arranged, but you

Know that all integers are between 1 and 1000 (including 1000). Besides, except that a number appears twice,

All other numbers appear only once. Suppose you can only process this array once and use an algorithm to find the duplicate array.

The number being answered. If you use the auxiliary storage method in your operation, then you can find that you don't need this method.

Type of algorithm?

50. Increase by 8 times without multiplication or addition. Now increase it by seven times in the same way.

C: creative application

5 1. Due to a work mistake, the salesgirl mistakenly sold the laptop of 20,000 yuan to Mr. Li at the price of 654.38+200,000 yuan.

How did Miss Wang's manager write to Mr. Li to get the money back?

52. How to apply computer technology to the elevator system of100 floor office building? How are you?

Optimize this application? How will the traffic, floor or time on weekdays affect this?

53. How to realize an operating system that can be stored in a file or copied from the Internet at any time?

Protective measures against illegal copying?

54. How do you redesign the ATM?

Suppose we want to operate a microwave oven through a computer, what kind of software will you develop to accomplish this task?

A mission?

56. How to design a coffee machine for a car?

56. If you wanted to add something to Microsoft Word system, what kind of content would you add?

57. What kind of keyboard would you design for a user with only one hand?

58. What kind of alarm clock would you design for the deaf?

Reference answer:

1, day 1 to 1,

On the second day, workers were required to return the 1 segment to the second segment.

On the third day, the 1 segment is given.

Day4 returned to 1 2 segment and gave 4 segments.

Day 5 and so on ...

2. In the face of such strange questions, some candidates are inseparable from their brains; Some candidates believe that

This question is actually very simple. Take out seven of the eight cakes and give them to seven people, and the remaining 1 cakes will be shared with the cake box.

To the eighth person.

If only one person wears a black hat, he will see everyone wearing a white hat, when the lights are turned off for the first time.

You have to slap yourself, so that more than one person will wear a black hat; If there are two black hats, the first time they both have only one.

Seeing the black hat on each other's head, they are not sure of their own color, but when they turn off the lights for the second time, they should understand.

If you wore a white hat, the other person should have slapped you last time, so you wore a black hat.

Then there will be a slap in the face; But the fact is, there was a slap in the face for the third time, indicating that there were more than two black people in the audience.

Hats, etc., should be closed several times, and some black hats.

5. For example, how to quickly estimate the height of the bracket and column, the radius of the ball, and calculate the volume of each part?

Wait a minute. The recruiter said: "As far as CNTOWER is concerned, it is still different from ordinary riddles or puzzles.

Yes We call this' quick estimation problem', and the main test is the ability of quick estimation, that is, developing software.

One of the necessary abilities. Of course, the topic is only a means, not an end. Of course, we must get a final result.

Yes, but it is more important to examine the process and method of candidates getting this result. "Mr Miller for the record.

The author illustrates a more reasonable answer with an example. He first drew a sketch of the CN tower on paper, and then quickly

Quickly estimate the height of the bracket and each column, as well as the radius of the ball, calculate the volume of each part, and then transport it with the density of each part.

Calculate and finally add up to get a result.

There are actually many topics in this category, such as: "Estimating the water quality of the Mississippi River." "If you

Is the governor of Tennessee. Please estimate how long it will take to control the pollution of Cumberland River. "

"Estimate the quality of rain that a person encounters after traveling in a light rain for five minutes."

Mr. Miller went on to explain: "Questions like this, including some reasoning questions, are all tested by people.

ProblemSolving is not a question for which you only remember the answer. "

For the purpose of company recruitment, Mr. Miller emphasized four points, which are common precautions for creative companies.

Paying attention to the quality of employees is the quality and ability that all people who want to realize their career dreams in well-known enterprises should have.

Requirement 1: RawSmart (pure wisdom), which has nothing to do with knowledge.

Requirement 2: Long-term potential (long-term learning ability).

Requirement 3: Technical skills.

Requirement 4: professionalism sm (professional attitude).

6. Her answer is: choose the first five floors, not. Observe the diamond size of each layer and pay attention to them.

. Then choose the last five layers, and choose the diamond whose size is close to the largest diamond that has ever appeared in the first five layers. She still is.

I don't know the exact answer to this question. "Maybe there is no exact answer, just a test of your thinking," she said.

Go ahead.

7. Analysis: A Cornell student wrote an article saying that he encountered this problem during an interview at Microsoft.

Minimum crossing time 19 minutes.

8. Burn both sides together.

9. One of the answers: The answer I heard from a computer science professor at MIT was first in the same place.

He has the largest area under such material conditions. Secondly, if it is square, rectangle or ellipse, it will be boring.

Just pick it up and throw it in the underpass! But the round cover can avoid this situation.

)

10, when this question seems confusing at first glance, you may have to ask how small this country is.

The interviewer may tell you this number from the beginning of the car, but he may also say, "I don't know, you tell me."

Me. "So, you said to yourself, the population of the United States is 275 million. You can guess that if the average family

The scale (including singles) is 2.5 people, and your computer will tell you that there are * * * 1. 1 100 million families. Do you remember?

I heard somewhere that every family has 1.8 cars, so there will be about 65438+98 million cars in the United States.

Cars. Then you just need to figure out how many gas stations you need to serve 6.5438+98 million vehicles, and you can solve the problem.

It's over. What matters is not the number of gas stations, but the way you get this number.

12, the answer is easy to calculate:

Suppose the distance from Los Angeles to new york is S ..

The distance a bird flies is (s/( 15+20))*30.

13, don't answer, see if you have the courage to stick to your point of view.

14, because human eyes are symmetrical in the horizontal direction.

15. Take out one from the first box, two from the second box and three from the third box.

And so on, according to its total.

16, more complicated:

First, fill a 3-quart bucket and pour in 5 quarts. Hereinafter referred to as 3->5)

Mark b 1 in the 5-quart barrel.

B, continue to fill 5 blanks with 3, and pour 5 pieces of water into 3 until b 1 is marked b2 in 3.

C, continue to fill 3 vacancies with 5, and pour 3 waters into 5 until b2.

D, empty 3. Pour the water from 5 into 3, labeled b3.

E, fill 5 empty 3, pour 5 water into 3 until 3 water reaches b3.

It's over. Now the water in 5 is standard 4 quarts dehydrated.

20. The prime numbers are off, and the rest are on.

29. When two numbers are allowed to be repeated.

The answer is x= 1, y = 4；; A knows the sum A=x+y=5, and B knows the product B=x*y=4.

There are two answers when two numbers are not allowed to be repeated.

Answer 1: x= 1, y = 6；; A knows the sum A=x+y=7, and B knows the product B=x*y=6.

Answer 2: x= 1, y = 8；; A knows the sum A=x+y=9, and B knows the product B=x*y=8.

Solution:

Let these two numbers be x and y.

A knows the sum of two numbers a = x+y;

B knows the product of two numbers b = x * y；;

This problem is divided into two situations:

Allow repetition, and use (1

Duplicates are not allowed. Use (1

When repetition is not allowed, that is, (1

1) The condition is that B doesn't know the answer.

& lt= & gtB=x*y solution is not unique.

= & gtB=x*y is a non-prime number.

Once again ∵ x ≠ y

∴ B ≠ k*k (where k∈N)

Conclusion (inference 1):

B=x*y is not a prime number and B ≠ k*k (where k∈N).

Namely: b ∈ (6,8, 10, 12, 14, 15, 18, 20 ...)

The proof process is simple.

2) Set the condition by the question: A doesn't know the answer.

& lt= & gtA=x+y solution is not unique.

= & gtA & gt= 5;

There are two situations:

When A=5 and A=6, X and Y have double solutions.

A> When =7, X and Y have triple or more solutions.

Suppose A=x+y=5.

There is a dual solution.

x 1= 1，y 1 = 4；

x2=2，y2=3

Substitute into the formula B=x*y:

b 1 = x 1 * y 1 = 1 * 4 = 4； (Deduct 1 Not satisfied, discarded)

B2 = x2 * y2 = 2 * 3 = 6；

Get the unique solution x=2, y=3, that is, A knows the answer.

Contradictory with the condition: "A doesn't know the answer",

So the assumption is not true, A=x+y≠5.

Suppose A=x+y=6.

There is a dual solution.

x 1= 1，y 1 = 5；

x2=2，y2=4

Substitute into the formula B=x*y:

b 1 = x 1 * y 1 = 1 * 5 = 5； (Deduct 1 Not satisfied, discarded)

B2 = x2 * y2 = 2 * 4 = 8；

The unique solution of x=2 and y=4 is obtained.

That is, A knows the answer.

Contradicting the condition: "A doesn't know the answer"

So the assumption is not true, A=x+y≠6.

When A & gt=7 o'clock

At least two solutions of x and y satisfy the inference 1.

b 1 = x 1 * y 1 = 2 *(A-2)

B2=x2*y2=3*(A-3)

match condition

Conclusion (Inference 2): A > = 7

3) Set the conditions by the topic: B said, "Then I know."

=>B can get a unique solution by knowing the condition B=x*y and inference (1)(2).

Namely:

A=x+y，A & gt= 7

B=x*y，B ∈(6，8， 10， 12， 14， 15， 16， 18，20...)

1 & lt； = x & lty & lt= 30

X and y have unique solutions.

When B=6, there are two groups of solutions.

x 1= 1，y 1=6

x2=2，y2 = 3(∵x2+y2 = 2+3 = 5 & lt； 7∴ irrelevant, give up)

The unique solutions x= 1 and y=6 are obtained.

When B=8, there are two groups of solutions.

x 1= 1，y 1=8

x2=2，y2 = 4(∵x2+y2 = 2+4 = 6 & lt； 7∴ irrelevant, give up)

The unique solutions x= 1 and y=8 are obtained.

When b > 8 o'clock: it is easy to prove that they are all multiple solutions.

Conclusion:

When B=6, there is a unique solution x= 1, y=6. When B=8, there is a unique solution x= 1, y=8.

4) Set the conditions by the topic: A said, "Then I know."

=>A knows that A=x+y and inference (3) can get a unique solution.

To sum up, there are two solutions to the original problem:

x 1= 1，y 1=6

x2= 1，y2=8

When x

In the same way, the unique solution x= 1 and y=4 can be obtained.

3 1、

Solution: 1000

Lg( 1000！ )=sum(Lg(n))

n= 1

By replacing the curve with three broken lines, you can get

10(0+ 1)/2+90( 1+2)/2+900(2+3)/2=2390

As an approximate result, it seems that 1500~3000 is correct.

32、F(n)= 1n & gt； 8n & lt； 12

f(n)= 2n & lt； 2

F(n)=3 n=6

F(n)= 4n = other

Use+-*/and sign(n) functions to combine the F(n) function.

sign(n)=0 n=0

sign(n)=- 1n & lt； 0

:sign(n)= 1n & gt； 0

Solution: Just pay attention to [sign(n-m)*sign(m-n)+ 1] and take 1 at n=m, and take 0 at other points.

34. An M-shaped painting will do.

The answer is to say goodbye to your family.