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#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "binary_search_tree.h"
#include "print_ascii_tree.h"
SearchTree make_empty(SearchTree t)
{
if(t != NULL) {
make_empty(t->left);
make_empty(t->right);
free(t);
}
return NULL;
}
/**
* find x or return NULL.
*/
Position find(elem_t x, SearchTree t)
{
if(t != NULL) {
if(t->elem == x) return t;
else if(t->elem > x) return find(x, t->right);
else return find(x, t->left);
}
return NULL;
}
Position find_min(SearchTree t)
{
if(t == NULL)
return NULL;
else if(t->left == NULL)
return t;
else
return find_min(t->left);
}
Position find_max(SearchTree t)
{
if(t == NULL)
return NULL;
else if(t->right == NULL)
return t;
else
return find_max(t->right);
}
SearchTree insert(elem_t x, SearchTree t)
{
if(t == NULL) {
t = malloc(sizeof(struct TreeNode));
t->elem = x;
t->left = NULL;
t->right = NULL;
} else if(x > t->elem)
t->right = insert(x, t->right);
else if(x < t->elem)
t->left = insert(x, t->left);
/* The t->elem = x need do nothing, already inserted */
return t;
}
SearchTree delete(elem_t x, SearchTree t)
{
Position p, tmp;
p = find(x, t);
if(p == NULL) {
/* elem x not found */
printf("x not found!(do nothing)\n");
} else if(p->left == NULL && p->right == NULL) {
free(p);
} else if(p->left == NULL) {
tmp = p;
p = p->right;
free(tmp);
} else if(p->right == NULL) {
tmp = p;
p = p->left;
free(tmp);
} else {
/* replace and delete */
tmp = find_min(p->right);
p->elem = tmp->elem;
t->right = delete(p->elem, t->right);
}
return t;
}
elem_t retrieve(Position p)
{
}
void print_tree_pre_order(SearchTree t)
{
if(t == NULL)
return;
print_tree_pre_order(t->left);
printf("%d ", t->elem);
print_tree_pre_order(t->right);
}
void test()
{
SearchTree t = NULL;
t = make_empty(t);
t = insert(1, t);
insert(4, t);
insert(3, t);
insert(2, t);
insert(10, t);
insert(12, t);
insert(-1, t);
print_tree_pre_order(t);
printf("\n");
print_ascii_tree(t);
}
int main()
{
test();
return 0;
}
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