Files
dlos/c/data_structures/heap.h

62 lines
1.9 KiB
C

#pragma once
// example of how the heap can be used
// here, each node value points to a plain int, but can substitute with other types
//
// // define a comparison function, a > b returns -1, a == b returns 0, a < b returns 1
// int compare_nodes(dlos_ComparableNode *a, dlos_ComparableNode *b) {
// int left = *((int*) a->value);
// int right = *((int*) b->value);
// if (left > right) {
// return -1;
// } else if (left == right) {
// return 0;
// } else {
// return 1;
// }
// }
//
// int main(int argc, char *argv[]) {
// int test_size = 10;
// int data_storage[] = {73, 6, 57, 88, 60, 42, 83, 72, 48, 85};
//
// // define an array of dlos_ComparableNode and fill it with the desired data
// // note: if using heap memory, just use for array, keep dlos_Heap in stack memory
// dlos_ComparableNode a[test_size];
// for (int i = 0; i < test_size; i++) {
// a[i].value = &data_storage[i];
// }
// // then define the dlos_Heap with the above array, compare function, and sizes
// dlos_Heap heap = {
// .size = test_size,
// .arr = a,
// .arr_size = test_size,
// .compare = compare_nodes
// };
//
// // then can use the heap; for example: order data into a max heap and sort it
// dlos_max_heap(&heap);
// dlos_sort_heap(&heap);
// for (int i = 0; i < test_size; i++) {
// if (i == 0) printf("sorted: ");
// printf("%d, ", *((int*) heap.arr[i].value));
// if (i == test_size - 1) printf("\n");
// }
// return 0;
// }
typedef struct dlos_ComparableNode {
void *value;
} dlos_ComparableNode;
typedef struct dlos_Heap {
int size;
dlos_ComparableNode *arr;
int arr_size;
int (*compare)(dlos_ComparableNode *a, dlos_ComparableNode *b);
} dlos_Heap;
void dlos_node_swap(dlos_ComparableNode *arr, int a, int b);
void dlos_sift_down(int i, dlos_Heap *h);
void dlos_max_heap(dlos_Heap *h);