Alternative earnings through internet.

Modern day students need not depend on their parents or elders for the pocket money. With the widespread use of internet there are lot of opportunities available for making money online. There are couple of online survey sites based in india which are providing reward points for filling up simple surveys ( http://xcel-onlinesurveys.com?sid=1&rid=AF24257&aid=0).
Lot of online work portals like rentacoder.com etc.. which provides works ranging from homework help to large industrial automation projects in the field of IT.

microsoft livesearch win rewards

Live.com microsoft's search initiative introduced a new feature which enables users to play the video search results with mouseover. This is one of the scoring points for Live.com apart from host of incentives you get by searching with Windows Live search engine.

Microsoft has comeup with free talktime offer to popularize there search. Click on the below link to find out more.
http://winwithsearch.com

Their searchperks program where you can win gifts based on the reward points in still on. Last date to register is 31st December,2008. Below link have the details.

http://www.getsearchperks.com/
I don't know whether it helps in popularizing their search , but certainly helps users in winning prizes.

There are 25 horses and only 5 tracks. No of matches to find top 3 horses.

Problem:
There are 25 horses and only 5 tracks. So only 5 horses can run the race at a time. How many minimum no of races should be conducted to find the 3 best horses?
Sol: The answer is 7.
Round 1: Take 5 horses at a time. 5 winners of each race will go to round2.
Round 2: Winner of this will be top most horse.(call it W1)
Round 3: Final race comprises of following 5 horses.
h1: 2nd horse of round2
h2:3rd horse of round2
h3:2nd horse of W1's group during round 1
h4:3rd horse of W1's group during round1
h5:2nd horse of h1's group during round1

Hat color problem--most asked question in interviews..

http://en.wikipedia.org/wiki/Prisoners_and_hats_puzzle

Two tribes one always tells true other false....

There were 2 tribes living on an island. The east tribal people always tell a lie. The west tribal people always tell the truth. Alan and Bryan came from the same tribe. However, we do not know which tribe they came from. When they were asked the marital status, Alan said: “Both of us are married.” But Bryan said: “I am not married”. Are they really married?


Ans:

Both are from same tribe. It means either both of them will lie or both will tell true. If we look at the statements both of them contradicts about Bryan's marital status. It means one of them is not telling truth, as they are from same tribe it concludes that they are from east tribe. It means Bryan is married and Alan's status is unclear.

Design a stack which have O(1) time complexity for finding the minimum element?

We can think of two different solutions -
Sol 1:
With additional memory where time complexity of findmin(),Push(),Pop() is O(1) but space complexity is O(n). Along with pushing the elements push the current minimum on to the stack. For pop operation pop 2 elements instead of 1 , it is still O(1).
For ex: Let us assume the following numbers which are pushed on to the stack.
4 2 9 3 6 1
Stack state will be something like below
4 4 2 2 9 2 3 2 6 2 1 1.
POP(x) = pop(), pop().
Where POP(x) is modified stack pop operation. pop() is standard pop() operation.
FINDMIN(x)=pop()
PUSH(x)=push() and push( MIN(pop(),elem)).
Where PUSH(x) is modified stack push operation. push() is standard push() operation.
Here storage needed for stack is 2n where n is number of elements in the stack.

Sol 2: