Created
March 26, 2013 12:53
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#include "heap.h" | |
#include <stdlib.h> | |
struct Heap { | |
int capacity; | |
int size; | |
int *heap; | |
int type; | |
}; | |
Heap *heapCreate(HeapType type) { | |
Heap *h; | |
h = malloc(sizeof(Heap)); | |
if(!h) | |
return NULL; | |
h->capacity = 16; | |
h->size = 0; | |
h->heap = malloc(sizeof(int) * h->capacity); | |
h->type = type; | |
} | |
void heapDestroy(Heap *h) { | |
free(h->heap); | |
free(h); | |
} | |
void heapInsert(Heap *h, int value) { | |
int *newHeap; | |
int i, j; | |
if(h->size == h->capacity) { | |
newHeap = realloc(h->heap, sizeof(int) * h->capacity * 2); | |
if(!newHeap) | |
return; | |
h->capacity *= 2; | |
h->heap = newHeap; | |
} | |
h->heap[h->size++] = value; | |
i = h->size - 1; | |
j = (i - 1) / 2; | |
while(h->heap[i] * h->type < h->heap[j] * h->type) { | |
h->heap[i] ^= h->heap[j]; | |
h->heap[j] ^= h->heap[i]; | |
h->heap[i] ^= h->heap[j]; | |
i = j; | |
j = (i - 1) / 2; | |
} | |
} | |
int heapExtract(Heap *h) { | |
int ret = h->heap[0]; | |
int l, r; | |
int i = 0, j, k, swap; | |
if(h->size == 1) | |
return h->heap[--h->size]; | |
else if(h->size == 2) { | |
h->heap[0] = h->heap[--h->size]; | |
return ret; | |
} | |
h->heap[0] = h->heap[--h->size]; | |
l = h->heap[0] - h->heap[1]; | |
r = h->heap[0] - h->heap[2]; | |
j = 1; | |
k = 2; | |
while(l * h->type > 0 && j < h->size || r * h->type > 0 && k < h->size) { | |
if(l * h->type > r * h->type) | |
swap = j; | |
else if(r * h->type > l * h->type) | |
swap = k; | |
h->heap[i] ^= h->heap[swap]; | |
h->heap[swap] ^= h->heap[i]; | |
h->heap[i] ^= h->heap[swap]; | |
i = swap; | |
j = i * 2 + 1; | |
k = i * 2 + 2; | |
l = h->heap[i] - h->heap[j]; | |
r = h->heap[i] - h->heap[k]; | |
} | |
return ret; | |
} | |
int heapEmpty(Heap *h) { | |
return h->size == 0; | |
} |
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#ifndef HEAP_H | |
#define HEAP_H | |
typedef struct Heap Heap; | |
typedef enum { | |
MAX_HEAP = -1, | |
MIN_HEAP = 1, | |
} HeapType; | |
Heap *heapCreate(HeapType type); | |
void heapDestroy(Heap *heap); | |
void heapInsert(Heap *heap, int value); | |
int heapExtract(Heap *heap); | |
int heapEmpty(Heap *h); | |
#endif /* HEAP_H */ |
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#include <stdio.h> | |
#include "heap.h" | |
int main(void) { | |
Heap *h = heapCreate(MIN_HEAP); | |
heapInsert(h, 5); | |
heapInsert(h, 2); | |
heapInsert(h, 17); | |
heapInsert(h, -2); | |
while(!heapEmpty(h)) | |
printf("minimum = %d\n", heapExtract(h)); | |
heapDestroy(h); | |
h = heapCreate(MAX_HEAP); | |
heapInsert(h, 5); | |
heapInsert(h, 2); | |
heapInsert(h, 17); | |
heapInsert(h, -2); | |
while(!heapEmpty(h)) | |
printf("maximum = %d\n", heapExtract(h)); | |
heapDestroy(h); | |
return 0; | |
} |
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