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#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include "avl_tree.h"
#include "print_ascii_tree.h"
AvlTree make_empty(AvlTree t)
{
if(t != NULL) {
make_empty(t->left);
make_empty(t->right);
free(t);
}
return NULL;
}
Position find(elem_t x, AvlTree t)
{
if(t == NULL)
return NULL;
else if(x == t->elem)
return t;
else if(x > t->elem)
return find(x, t->right);
else if(x < t->elem)
return find(x, t->left);
}
Position find_min(AvlTree t)
{
if(t == NULL)
return NULL;
else if(t->left == NULL)
return t;
else
return find_min(t->left);
}
Position find_max(AvlTree t)
{
if(t == NULL)
return NULL;
else if(t->right == NULL)
return t;
else
return find_max(t->right);
}
static int height(Position p)
{
return p == NULL ? -1 : p->height;
}
static Position single_rotate_with_left(Position p)
{
Position p_left;
p_left = p->left;
p->left = p_left->right;
p_left->right = p;
/* derectly use ->height may case some problem */
p->height = MAX(height(p->left), height(p->right)) + 1;
p_left->height = MAX(height(p_left->left), p->height) + 1;
/* return new Node */
return p_left;
}
static Position single_rotate_with_right(Position p)
{
Position p_right;
p_right = p->right;
p->right = p_right->left;
p_right->left = p;
p->height = MAX(height(p->left), height(p->right)) + 1;
p_right->height = MAX(height(p_right->right), p->height) + 1;
/* return new node */
return p_right;
}
static Position double_rotate_with_left(Position p)
{
p->left = single_rotate_with_right(p->left);
return single_rotate_with_left(p);
}
static Position double_rotate_with_right(Position p)
{
p->right = single_rotate_with_left(p->right);
return single_rotate_with_right(p);
}
AvlTree insert(elem_t x, AvlTree t)
{
if(t == NULL) {
t = malloc(sizeof(struct AvlNode));
t->elem = x;
t->height = 0;
t->left = t->right = NULL;
} else if(x > t->elem) {
t->right = insert(x, t->right);
/* > 1 or == 2? */
if(height(t->right) - height(t->left) > 1) {
if(x > t->right->elem)
t = single_rotate_with_right(t);
if(x < t->right->elem)
t = double_rotate_with_right(t);
}
} else if(x < t->elem) {
t->left = insert(x, t->left);
if(height(t->left) - height(t->right) == 2) {
if(x < t->left->elem)
t = single_rotate_with_left(t);
if(x > t->left->elem)
t = double_rotate_with_left(t);
}
}
/* else do nothing, but update the height */
t->height = MAX(height(t->left), height(t->right)) + 1;
return t;
}
/* lazy delete ? */
AvlTree delete(elem_t x, AvlTree t)
{
}
void test()
{
AvlTree t = NULL;
t = insert(4, t);
t = insert(3, t);
t = insert(2, t);
t = insert(1, t);
t = insert(8, t);
t = insert(9, t);
printf("min:%d\n", find_min(t)->elem);
printf("max:%d\n", find_max(t)->elem);
printf("find 2:%d\n", find(2, t)->elem);
print_ascii_tree(t);
}
int main()
{
test();
return 0;
}
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