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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;
}
AvlTree insert_nonrecursive(elem_t x, AvlTree t)
{
Position tmp;
Position prev[100] ;
Position p = t;
int i = 0;
int j;
/* index 0 not used */
prev[i] = p;
while(p) {
if(x < p->elem) {
prev[++i] = p;
p = p->left;
} else if(x > p->elem) {
prev[++i] = p;
p = p->right;
} else
return t;
}
tmp = malloc(sizeof(struct AvlNode));
tmp->elem = x;
tmp->left = tmp->right = NULL;
tmp->height = 0;
if(!prev[i]) {
return tmp;
} else if(x < prev[i]->elem) {
prev[i]->left = tmp;
prev[i]->height++;
if(i - 1 > 0) {
if(prev[i - 1]->left == prev[i]
&& prev[i]->height - height(prev[i - 1]->right) == 2)
prev[i - 2] = single_rotate_with_left(prev[i - 1]);
else if(prev[i - 1]->right == prev[i]
&& prev[i]->height - height(prev[i - 1]->left) == 2)
prev[i - 2] = double_rotate_with_left(prev[i - 1]);
}
}
else {
prev[i]->right = tmp;
prev[i]->height++;
if(i - 1 > 0) {
if(prev[i - 1]->right == prev[i]
&& prev[i]->height - height(prev[i - 1]->left) == 2)
prev[i - 2] = single_rotate_with_right(prev[i - 1]);
else if(prev[i - 1]->left == prev[i]
&& prev[i]->height - height(prev[i - 1]->right) == 2) {
prev[i - 2] = double_rotate_with_right(prev[i - 2]);
}
}
}
return t;
}
/* lazy delete ? */
AvlTree delete(elem_t x, AvlTree t)
{
}
void test()
{
int i;
AvlTree t = NULL;
for(i = 0; i < 3; i++) {
t = insert_nonrecursive(i + 1, t);
}
printf("min:%d\n", find_min(t)->elem);
printf("max:%d\n", find_max(t)->elem);
print_ascii_tree(t);
}
int main()
{
test();
return 0;
}
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