avl tree constructor code example
Example: avl tree c implementation
#include <stdio.h>
#include "avltree.h"
void dispose(node* t)
{
if( t != NULL )
{
dispose( t->left );
dispose( t->right );
free( t );
}
}
node* find(int e, node* t )
{
if( t == NULL )
return NULL;
if( e < t->data )
return find( e, t->left );
else if( e > t->data )
return find( e, t->right );
else
return t;
}
node* find_min( node* t )
{
if( t == NULL )
return NULL;
else if( t->left == NULL )
return t;
else
return find_min( t->left );
}
node* find_max( node* t )
{
if( t != NULL )
while( t->right != NULL )
t = t->right;
return t;
}
static int height( node* n )
{
if( n == NULL )
return -1;
else
return n->height;
}
static int max( int l, int r)
{
return l > r ? l: r;
}
static node* single_rotate_with_left( node* k2 )
{
node* k1 = NULL;
k1 = k2->left;
k2->left = k1->right;
k1->right = k2;
k2->height = max( height( k2->left ), height( k2->right ) ) + 1;
k1->height = max( height( k1->left ), k2->height ) + 1;
return k1;
}
static node* single_rotate_with_right( node* k1 )
{
node* k2;
k2 = k1->right;
k1->right = k2->left;
k2->left = k1;
k1->height = max( height( k1->left ), height( k1->right ) ) + 1;
k2->height = max( height( k2->right ), k1->height ) + 1;
return k2;
}
static node* double_rotate_with_left( node* k3 )
{
k3->left = single_rotate_with_right( k3->left );
return single_rotate_with_left( k3 );
}
static node* double_rotate_with_right( node* k1 )
{
k1->right = single_rotate_with_left( k1->right );
return single_rotate_with_right( k1 );
}
node* insert(int e, node* t )
{
if( t == NULL )
{
t = (node*)malloc(sizeof(node));
if( t == NULL )
{
fprintf (stderr, "Out of memory!!! (insert)\n");
exit(1);
}
else
{
t->data = e;
t->height = 0;
t->left = t->right = NULL;
}
}
else if( e < t->data )
{
t->left = insert( e, t->left );
if( height( t->left ) - height( t->right ) == 2 )
if( e < t->left->data )
t = single_rotate_with_left( t );
else
t = double_rotate_with_left( t );
}
else if( e > t->data )
{
t->right = insert( e, t->right );
if( height( t->right ) - height( t->left ) == 2 )
if( e > t->right->data )
t = single_rotate_with_right( t );
else
t = double_rotate_with_right( t );
}
t->height = max( height( t->left ), height( t->right ) ) + 1;
return t;
}
node* delete( int e, node* t )
{
printf( "Sorry; Delete is unimplemented; %d remains\n", e );
return t;
}
int get(node* n)
{
return n->data;
}
void display_avl(node* t)
{
if (t == NULL)
return;
printf("%d",t->data);
if(t->left != NULL)
printf("(L:%d)",t->left->data);
if(t->right != NULL)
printf("(R:%d)",t->right->data);
printf("\n");
display_avl(t->left);
display_avl(t->right);
}