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56 lines
1.9 KiB
C
56 lines
1.9 KiB
C
#ifndef __PRIORITY_QUEUE_H__
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#define __PRIORITY_QUEUE_H__
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#include "vector.h"
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/* Priority queue
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* Priority queues are designed such that its first element is always the greatest of the elements it contains.
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* This context is similar to a heap, where elements can be inserted at any moment, and only the max heap element can be
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* retrieved (the one at the top in the priority queue).
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* Priority queues are implemented as Vectors. Elements are popped from the "back" of Vector, which is known as the top
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* of the priority queue.
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*/
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typedef struct {
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Vector *v;
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int (*cmp)(void *, void *);
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} PriorityQueue;
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/* Construct priority queue
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* Constructs a priority_queue container adaptor object.
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*/
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PriorityQueue *__newPriorityQueueSize(size_t elemSize, size_t cap, int (*cmp)(void *, void *));
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#define NewPriorityQueue(type, cap, cmp) __newPriorityQueueSize(sizeof(type), cap, cmp)
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/* Return size
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* Returns the number of elements in the priority_queue.
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*/
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size_t Priority_Queue_Size(PriorityQueue *pq);
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/* Access top element
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* Copy the top element in the priority_queue to ptr.
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* The top element is the element that compares higher in the priority_queue.
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*/
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int Priority_Queue_Top(PriorityQueue *pq, void *ptr);
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/* Insert element
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* Inserts a new element in the priority_queue.
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*/
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size_t __priority_Queue_PushPtr(PriorityQueue *pq, void *elem);
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#define Priority_Queue_Push(pq, elem) __priority_Queue_PushPtr(pq, &(typeof(elem)){elem})
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/* Remove top element
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* Removes the element on top of the priority_queue, effectively reducing its size by one. The element removed is the
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* one with the highest value.
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* The value of this element can be retrieved before being popped by calling Priority_Queue_Top.
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*/
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void Priority_Queue_Pop(PriorityQueue *pq);
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/* free the priority queue and the underlying data. Does not release its elements if
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* they are pointers */
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void Priority_Queue_Free(PriorityQueue *pq);
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#endif //__PRIORITY_QUEUE_H__
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