Mastering Algorithms with C

Name

heap_init

Synopsis

void heap_init(Heap *heap, int (*compare)(const void *key1, const void *key2) 
   void (*destroy)(void *data));

Return Value

None.

Description

Initializes the heap specified by heap. This operation must be called for a heap before the heap can be used with any other operation. The compare argument is a function used by various heap operations to compare nodes when fixing the heap. This function should return 1 if key1 > key2, if key1 = key2, and -1 if key1 < key2 for a top-heavy heap. For a bottom-heavy heap, compare should reverse the cases that return 1 and -1. The destroy argument provides a way to free dynamically allocated data when heap_destroy is called. For example, if the heap contains data dynamically allocated using malloc, destroy should be set to free to free the data as the heap is destroyed. For structured data containing several dynamically allocated members, destroy should be set to a user-defined function that calls free for each dynamically allocated member as well as for the structure itself. For a heap containing data that should not be freed, destroy should be set to NULL.

Complexity

O (1)