void *minheap_remove(struct minheap *heap) {
assert(heap != NULL);
assert(heap->size > 0);
void *min = heap->values[0];
heap->values[0] = heap->values[heap->size-1];
--heap->size;
// reallocate when too much capacity
if (heap->size <= heap->capacity/2) {
int new_capacity = heap->capacity/2;
void **new_values = (void**)realloc(heap->values,
new_capacity*sizeof(void*));
if (new_capacity == 0)
heap->values = NULL;
else heap->values = new_values;
heap->capacity = new_capacity;
}
int cur_idx = 0;
int swap_idx = minheap_get_swap_idx(heap, cur_idx);
while (swap_idx > 0) {
utils_swap(&heap->values[cur_idx], &heap->values[swap_idx]);
cur_idx = swap_idx;
swap_idx = minheap_get_swap_idx(heap, cur_idx);
}
return min;
}
int utils_permute_inverse(bmp_byte_t *pixels, size_t size, bmp_word_t seed)
{
int *rand_numbers = utils_generate_rand_numbers(size, seed);
if (rand_numbers == NULL)
{
return -1;
}
int i;
for (i = 0; i < size; i++)
{
utils_swap(pixels, i, rand_numbers[size - 1 - i]);
}
free(rand_numbers);
return 0;
}
int minheap_add(struct minheap *heap, void *value) {
assert(heap != NULL);
// empty heap
if (heap->size == 0) {
assert(heap->values == NULL);
assert(heap->capacity == 0);
void **values = (void**)malloc(sizeof(void*));
if (values == NULL)
return -1;
values[0] = value;
heap->values = values;
heap->size = 1;
heap->capacity = 1;
return 0;
}
// heap is at capacity, double capacity
if (heap->size == heap->capacity) {
int new_capacity = heap->capacity*2;
void **new_values = (void**)realloc(heap->values,
sizeof(void*)*new_capacity);
if (new_values == NULL)
return -1;
heap->values = new_values;
heap->capacity = new_capacity;
}
heap->values[heap->size] = value;
++heap->size;
int cur_pos = heap->size-1;
int par_pos = (cur_pos-1)/2;
while (heap->cmp(heap->values[cur_pos], heap->values[par_pos]) == -1 &&
par_pos >= 0) {
utils_swap(&heap->values[cur_pos], &heap->values[par_pos]);
cur_pos = par_pos;
par_pos = (par_pos-1)/2;
}
return 0;
}
