17 lines
956 B
Markdown
17 lines
956 B
Markdown
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A data-structure often associated with the queue is the stack.
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That's because they are basically the opposite of one another.
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While the queue works on the FIFO-principle the stack works
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on the **LIFO**-principle (**L**ast **i**n **f**irst **o**ut).
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Similar two the queue we have three basic operations, but they are called
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different to distinguish between the stack and the queue.
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- We put something at the top of the stack. That is called push.
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- We take something from the top of the stack. That is called pop.
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- As with the queue we sometimes one to just take a look at the top of the stack.
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So a peak operation is nice, but not necessary
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Stacks are useful data-structures for parsing or when you want follow some data to the end
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and then back trace to a previous state, like in depth-fist-search.
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These are just some use cases for stacks, but they have many more.
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Your task is to implement the push, pop and peak functions for the stack.
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