Queue in swift
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Queues follow the first-in, first-out (FIFO) principle. Common queue operations include enqueue to add an item to the back of the queue and dequeue to remove an item from the front. Queues can be implemented using arrays, linked lists, ring buffers, or two stacks.
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var queue = QueueRingBuffer<String>(count: 4)
Write
Read
queue.enqueue(“섭")
queue.enqueue(“준호”)
queue.enqueue(“태현”)
queue.dequeue()
queue
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queue.peek “ ”
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queue.enqueue(“경준”) true
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queue.dequeue() “ ”
queue.dequeue() “ ”
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queue.isEmpty true](https://image.slidesharecdn.com/queue-200115143113/85/Queue-in-swift-8-320.jpg)
Queue in swift
- 1. Queues
- 3. Common operations enqueue( ) : . true . dequeue( ) : . isEmpty : . Peek : .
- 4. Example of a queue enqueue(“ ”)enqueue(“ ”) front back enqueue(“ ”)enqueue(“ ”)enqueue(“ ”)enqueue(“ ”)enqueue(“ ”)enqueue(“ ”)dequeue()dequeue()dequeue()dequeue()dequeue()
- 5. queue 4 (Array) (Doubly linked list) (Ring buffer) (Two stacks)
- 7. ? . next next next prev prev prev head tail
- 8. ? var queue = QueueRingBuffer<String>(count: 4) Write Read queue.enqueue(“섭") queue.enqueue(“준호”) queue.enqueue(“태현”) queue.dequeue() queue [] true true true [ , , ] “ ” queue [ , ] queue.peek “ ” queue [ , ] queue.enqueue(“경준”) true queue [ , , ] queue.dequeue() “ ” queue.dequeue() “ ” queue “ ” queue.dequeue() “ ” queue.isEmpty true
- 9. 1 Left Stack Dequeue Right Stack Enqueue 2 3 eneque(1)eneque(2)eneque(3)dequeue()
- 10. Key points • FIFO(First In First Out) . • Enqueue . • Dequeue . • . • . • dequeue O(1) . • .