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#include <stdio.h>
#include <stdlib.h>
typedef struct node *position;
typedef int ElementTP;
struct node {
position parent;
ElementTP element;
position lchild;
position rchild;
};
typedef struct node *TREE;
void print_sorted_tree(TREE);
position find_min(TREE);
position find_max(TREE);
position find_value(TREE, ElementTP);
position insert_value(TREE, ElementTP);
ElementTP delete_node(position);
static int is_root(position);
static int is_leaf(position);
static ElementTP delete_leaf(position);
static void insert_node_to_nonempty_tree(TREE, position);
void main(void)
{
TREE tr;
position np;
ElementTP element;
tr = NULL;
tr = insert_value(tr, 18);
tr = insert_value(tr, 5);
tr = insert_value(tr, 2);
tr = insert_value(tr, 8);
tr = insert_value(tr, 81);
tr = insert_value(tr, 101);
printf("Original:\n");
print_sorted_tree(tr);
np = find_value(tr, 8);
if(np != NULL) {
delete_node(np);
printf("After deletion:\n");
print_sorted_tree(tr);
}
}
* print values of the tree in sorted order
*/
void print_sorted_tree(TREE tr)
{
if (tr == NULL) return;
print_sorted_tree(tr->lchild);
printf("%d \n", tr->element);
print_sorted_tree(tr->rchild);
}
* search for minimum value
* traverse lchild
*/
position find_min(TREE tr)
{
position np;
np = tr;
if (np == NULL) return NULL;
while(np->lchild != NULL) {
np = np->lchild;
}
return np;
}
* search for maximum value
* traverse rchild
*/
position find_max(TREE tr)
{
position np;
np = tr;
if (np == NULL) return NULL;
while(np->rchild != NULL) {
np = np->rchild;
}
return np;
}
* search for value
*
*/
position find_value(TREE tr, ElementTP value)
{
if (tr == NULL) return NULL;
if (tr->element == value) {
return tr;
}
else if (value < tr->element) {
return find_value(tr->lchild, value);
}
else {
return find_value(tr->rchild, value);
}
}
* delete node np
*/
ElementTP delete_node(position np)
{
position replace;
ElementTP element;
if (is_leaf(np)) {
return delete_leaf(np);
}
else {
replace = (np->lchild != NULL) ? find_max(np->lchild) : find_min(np->rchild);
element = np->element;
np->element = delete_node(replace);
return element;
}
}
* insert a value into the tree
* return root address of the tree
*/
position insert_value(TREE tr, ElementTP value) {
position np;
np = (position) malloc(sizeof(struct node));
np->element = value;
np->parent = NULL;
np->lchild = NULL;
np->rchild = NULL;
if (tr == NULL) tr = np;
else {
insert_node_to_nonempty_tree(tr, np);
}
return tr;
}
* np is root?
*/
static int is_root(position np)
{
return (np->parent == NULL);
}
* np is leaf?
*/
static int is_leaf(position np)
{
return (np->lchild == NULL && np->rchild == NULL);
}
* if an element is a leaf,
* then it could be removed with no side effect.
*/
static ElementTP delete_leaf(position np)
{
ElementTP element;
position parent;
element = np->element;
parent = np->parent;
if(!is_root(np)) {
if (parent->lchild == np) {
parent->lchild = NULL;
}
else {
parent->rchild = NULL;
}
}
free(np);
return element;
}
* insert a node to a non-empty tree
* called by insert_value()
*/
static void insert_node_to_nonempty_tree(TREE tr, position np)
{
if(np->element <= tr->element) {
if (tr->lchild == NULL) {
tr->lchild = np;
np->parent = tr;
return;
}
else {
insert_node_to_nonempty_tree(tr->lchild, np);
}
}
else if(np->element > tr->element) {
if (tr->rchild == NULL) {
tr->rchild = np;
np->parent = tr;
return;
}
else {
insert_node_to_nonempty_tree(tr->rchild, np);
}
}
}
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