0. You have 2 supposedly unbreakable light bulbs and a 100-floor building. Using fewest possible drops, determine how much of an impact this type of light bulb can withstand. (i.e. it can withstand a drop from 17th floor, but breaks from the 18th).
Note that the ever-popular binary search will give you a worst case of 50 drops. You should be able to do it with under 20.
1. There are n gas stations positioned along a circular road. Each has a limited supply of gas. You can only drive clockwise around the road. You start with zero gas. Knowing how much gas you need to get from each gas station to the next and how much gas you can get at each station, design an algorithm to find the gas station you need to start at to get all the way around the circle.
2. Out of 10 coins, one weighs less then the others. You have a scale.
How can you determine which one weighs less in 3 weighs?
Now how would you do it if you didn't know if the odd coin weighs less or more?
3. What is the next line in the following sequence:
1
11
21
Answer: it's 1211 and the next is 111221
4. There are 3 baskets. one of them have apples, one has oranges only and the other has mixture of apples and oranges. The labels on their baskets always lie. (i.e. if the label says oranges, you are sure that it doesn’t have oranges only,it could be a mixture) The task is to pick one basket and pick only one fruit from it and then correctly label all the three baskets.
5. You have 8 balls. One of them is defective and weighs less than others. You have a balance to measure balls against each other. In 2 weighings how do you find the defective one?
6. Why is a manhole cover round?
7. How many cars are there in the USA?
8. You’ve got someone working for you for seven days and a gold bar to pay them. The gold bar is segmented into seven connected pieces. You must give them a piece of gold at the end of every day. If you are only allowed to make two breaks in the gold bar, how do you pay your worker?
9. If you had an infinite supply of water and a 5 quart and 3 quart pail, how would you measure exactly 4 quarts?
10. You have a bucket of jelly beans. Some are red, some are blue, and some green. With your eyes closed, pick out 2 of a like color. How many do you have to grab to be sure you have 2 of the same?
11. Imagine you are standing in front of a mirror, facing it. Raise your left hand. Raise your right hand. Look at your reflection. When you raise your left hand your reflection raises what appears to be his right hand. But when you tilt your head up, your reflection does too, and does not appear to tilt his/her head down. Why is it that the mirror appears to reverse left and right, but not up and down?
10. You have 5 jars of pills. Each pill weighs 10 gram, except for contaminated pills contained in one jar, where each pill weighs 9 gm. Given a scale, how could you tell which jar had the contaminated pills in just one measurement?
12. If you had an infinite supply of water and a 5 quart and 3 quart pail, how would you measure exactly 4 quarts?
13. You have a bucket of jelly beans. Some are red, some are blue, and some green. With your eyes closed, pick out 2 of a like color. How many do you have to grab to be sure you have 2 of the same?
14. Which way should the key turn in a car door to unlock it?
15. If you could remove any of the 50 states, which state would it be and why?
16. There are four dogs/ants/people at four corners of a square of unit distance. At the same instant all of them start running with unit speed towards the person on their clockwise direction and will always run towards that target. How long does it take for them to meet and where?
17. (fram Tara Hovel) A helicopter drops two trains, each on a parachute, onto a straight infinite railway line. There is an undefined distance between the two trains. Each faces the same direction, and upon landing, the parachute attached to each train falls to the ground next to the train and detaches. Each train has a microchip that controls its motion. The chips are identical. There is no way for the trains to know where they are. You need to write the code in the chip to make the trains bump into each other. Each line of code takes a single clock cycle to execute.
