IMPLEMENT 3 STACKS IN A SINGLE ARRAY HOW TO

If you have a situation in which you will frequently move elements between stacks, storing the stacks in a single array would be more efficient. Update: It would be most useful in certain specialized cases. Rarely would you even think of doing this. With the amount of memory typically available these days, combining stacks in this way would be a rather extreme optimization. You then need to be able to search and fill these gaps later on when you add a new element. When elements are removed from one stack, it may leave gaps. Elements of the three stacks will be interspersed with each other. However, the stacks in a single array would also be more complicated to manage. Combining them to a single array would reduce the amount of 'extra' memory that is pre-allocated for future operations, and you would have to allocate new memory fewer times. If you have three stacks in three separate arrays, each one would need pre-allocated space to allow for future elements, and each one would need new memory to be allocated if it fills up. Implementing multiple stacks in a single (linked list) array could use memory more efficiently. While there may be some strange edge case like 'each stack can have up to a million items, but when one grows the others shrink so the total space never changes' that happen in the real world, that is not why you're being asked to solve the problem.

IMPLEMENT 3 STACKS IN A SINGLE ARRAY HOW TO

Similarly your question will test if you know how to manage memory, restructure a simple approach (stacks) to handle a strange constraint, and think about clever things like not moving the item from stack to stack but just updating the links. The point of the question wasn't that people need to measure height with barometers regularly (or ever) but to see if the candidate knew the formula for pressure and height.

Thus, the total length of our values array will be 3 the stack size (since we’re initializing. My favourite 'wrong' answers involve dropping it from the top, measuring the time till it hits the ground, and applying a formula, or seeking out the architect/janitor/owner of the building and offering a trade: I'll give you this expensive barometer if you tell me how tall that building is. The exercise is: Describe how you could use a single array to implement three stacks. In Physics there's a story about the question 'how would you measure the height of a building with a barometer?' The 'right' answer involves measuring the air pressure at the top and bottom and applying a formula. People who ask them believe they serve as a good substitute for the genuinely difficult challenges in their coding that cannot be explained in such a short time (and whose solutions cannot be evaluated so quickly either.) They are a challenge to see if you can think your way through something difficult. Many interview questions serve no practical purpose.

Implement 3 stacks in a single array