Premski - Puzzle Corner

Triangle problem

2008-06-24 23:31:30

given a triangle ABC, how would you use only a compass and a straight edge to find a point P such that triangles ABP, ACP & BCP have equal perimeters?(Assume that ABC is constructed so that a solution does exist) Click HERE to answer this question!

2008-06-24 23:28:10

#\r\n\r\nSay we have a data structure as follows:\r\n\r\nenum {RED,BLUE,GREEN};\r\nstruct Ball\r\n{\r\n /*...*/\r\n int color;\r\n};\r\n\r\nint ColorOfBall(Ball b)\r\n{\r\n return b.color;\r\n}\r\nBall arr[SIZE];\r\n\r\nThe array arr consists of balls of with one of the three colours\r\n(Red,Green,Blue). Now we need to sort the array in such a way that all\r\nthe Red coloured balls come first, followed by blue and then green.\r\n\r\nThe restriction is that call to function ColorOfBall is a very costly\r\noperation. You have to use it as less as possible. (In other words we\r\nwould be looking for the solution with least number of calls to the\r\nfunction ColorOfBall.)\r\n Click HERE to answer this question!

Multiplication of numbers

2008-06-16 04:56:01

There is an array A[N] of N numbers. You have to compose an array Output[N] such that Output[i] will be equal to multiplication of all the elements of A[N] except A[i]. For example Output[0] will be multiplication of A[1] to A[N-1] and Output[1] will be multiplication of A[0] and from A[2] to A[N-1].\r\n\r\nSolve it without division operator and in O(n). Click HERE to answer this question!

Probability to spot a car

2008-06-16 04:16:49

If the probability of observing a car in 30 minutes on a highway is 0.95, what is the probability of observing a car in 10 minutes Click HERE to answer this question!

Preorder traversal

2008-04-04 00:38:02

Write a c code (both recursive & non recursive) to do preorder traversal\r\nof a binary tree Click HERE to answer this question!

Minimum possible races

2008-03-14 11:29:29

There are 25 horses and 5 lanes. You have no idea about which horse is better than other. Find in minimum possible races, the first three fastest running horses. Click HERE to answer this question!

What is the age of my children?

2008-03-13 18:29:30

Mr. X meet Mr. Y during an early morning walk.\r\n\r\nMr Y asks the age of Mr. X\\\'s children and Mr. X is a math professor so gives Mr Y a problem to solve.\r\n\r\nMr X says \r\n-> I have 3 children \r\n-> The product of their ages is 36\r\n-> The sum of their age is equal to the number of houses in my street.\r\n-> And my first daughter has blue eyes.\r\n\r\nUsing these clues Mr Y was able to say the ages of the 3 children. Click HERE to answer this question!

Lucky Vs Unlucky Number

2008-03-13 18:28:26

In Russia you get into a bus, take a ticket, and sometimes say : Wow, a lucky number! Bus tickets are numbered by 6-digit numbers, and a lucky ticket has the sum of 3 first digits being equal to the sum of 3 last digits. When we were in high school (guys from math school No. 7 might remember that ) we had to write a code that prints out all the lucky tickets\\\' numbers; at least I did, to show my loyalty to the progammers\\\' clan. Now, if you add up all the lucky tickets\\\' numbers you will find out that 13 (the most unlucky number) is a divisor of the result. Can you prove it (without writing a code)? Click HERE to answer this question!

Bank card fraud

2007-11-03 05:31:52

A bank has a collection of n bank cards that theyââ�¬â�¢ve confiscated, suspecting them of being used in a fraud. Each bank card corresponds to a unique account in the bank. Each account can have many cards corresponding to it, and weââ�¬â�¢ll say that two bank cards are equivalent if they correspond to the same account. The only way to say 2 cards are equivalent is by using a high-tech ââ�¬Å�equivalence-testerââ�¬Â� that takes in 2 cards, and after performing some computations, determines whether they are equivalent. \r\n\r\nTheir question is the following: among the collection of n cards, is there a set of more than n/2 of them that are all equivalent to one another? Assume that the only feasible operations you can do with the cards are to pick two of them and plug them in to the equivalence tester. Answer in O(n) Click HERE to answer this question!

A google puzzle

2007-10-29 03:31:00

Not sure if this really is a valid puzzle, but WTH, one of you smart guys might find something after all. Enjoy!\r\n\r\n<img src=\\"http://blogoscoped.com/files/google-riddle-2007-10.png\\" alt=\\"\\" style=\\"width: 500px; height: 300px;\\"></img> Click HERE to answer this question!