Queue vs Dequeue in java

Deque is short for “double ended queue”. With an ordinary queue, you add things to one end and take them from the other. With a double ended queue, you can add things to either end, and take them from either end. That makes it a bit more versatile; for example, you could use it as …

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Implementing a HashMap in C

Well if you know the basics behind them, it shouldn’t be too hard. Generally you create an array called “buckets” that contain the key and value, with an optional pointer to create a linked list. When you access the hash table with a key, you process the key with a custom hash function which will …

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Linked List vs Vector

Vector is another name for dynamic arrays. It is the name used for the dynamic array data structure in C++. If you have experience in Java you may know them with the name ArrayList. (Java also has an old collection class called Vector that is not used nowadays because of problems in how it was …

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How do I instantiate a Queue object in java?

A Queue is an interface, which means you cannot construct a Queue directly. The best option is to construct off a class that already implements the Queue interface, like one of the following: AbstractQueue, ArrayBlockingQueue, ArrayDeque, ConcurrentLinkedQueue, DelayQueue, LinkedBlockingQueue, LinkedList, PriorityBlockingQueue, PriorityQueue, or SynchronousQueue. An alternative is to write your own class which implements the necessary Queue interface. It is not needed except in those rare cases where you wish to …

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What is the difference between a map and a dictionary?

Two terms for the same thing: “Map” is used by Java, C++ “Dictionary” is used by .Net, Python “Associative array” is used by PHP “Map” is the correct mathematical term, but it is avoided because it has a separate meaning in functional programming. Some languages use still other terms (“Object” in Javascript, “Hash” in Ruby, “Table” in Lua), but those all …

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