1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 | #include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
#include <assert.h>
// BST - CORRECT
typedef struct _BSTNode {
int value; // ≥4 bytes¹
struct _BSTNode* left; // ≥8 bytes¹
struct _BSTNode* right; // ≥8 bytes¹
} BSTNode; // ≥20 bytes¹
// ¹ on our platform
void insert(int value, BSTNode** a_root) {
// If tree is empty, then insert the value as the root of this tree.
if(*a_root == NULL) {
// CREATE new node
BSTNode* new_node = malloc(sizeof(*new_node));
*new_node = (BSTNode) { .value = value, .left = NULL, .right = NULL };
// CONNECT new node to the tree
*a_root = new_node;
}
// Otherwise, insert in either the left or right subtree, depending on the value.
else if(value < (*a_root) -> value) {
insert(value, &((*a_root) -> left));
}
else if(value >= (*a_root) -> value) {
insert(value, &((*a_root) -> right));
}
}
void print_tree_in_order(BSTNode* root) { // IN-ORDER traversal: left, root, right
if(root != NULL) {
print_tree_in_order(root -> left); // print the left subtree (recursively)
printf("-[%d]-", root -> value); // print value in the root
print_tree_in_order(root -> right); // print the right subtree (recursively)
}
}
void destroy_tree(BSTNode** a_root) { //
if(*a_root != NULL) {
destroy_tree(&((*a_root) -> left));
assert((*a_root) -> left == NULL); // left subtree has been destroyed and is empty
destroy_tree(&((*a_root) -> right));
assert((*a_root) -> right == NULL);
free(*a_root); // deallocate
*a_root = NULL; // set to NULL to indicate that it is empty
}
assert(*a_root == NULL); // Tree must be empty
}
int main(int argc, char* argv[]) {
// Empty list
BSTNode* root = NULL;
// Insert a value
insert(4, &root);
insert(2, &root);
insert(6, &root);
insert(1, &root);
insert(3, &root);
insert(5, &root);
insert(7, &root);
// Print
print_tree_in_order(root);
// Free
destroy_tree(&root);
return EXIT_SUCCESS;
}
/* vim: set tabstop=4 shiftwidth=4 fileencoding=utf-8 noexpandtab: */
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