AVL Tree single rotation and double Rotation Algorithm (c)

To understand this code, you must understand the single rotation and double rotation algorithms. Second, we need to really understand recursive usage.

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/*
* Avl tree.
*/
# Include <stdio. h>
# Include <stdlib. h>
# Include <string. h>
 
Struct AvlNode;
Typedef struct AvlNode * Position;
Typedef struct AvlNode * AvlTree;
 
Struct AvlNode
{
Int Element;
AvlTree Left;
AvlTree Right;
Int Height;
};
 
Int Max (int a, int B)
{
Return (a> B )? A: B;
}
 
Static int HeightAvl (Position P)
{
If (P = NULL)
{
Return-1;
}
Else
{
Return P-> Height;
}
 
}
 
 
Static Position SingleRotateWithLeft (Position K2)
{
Position K1;
 
K1 = K2-> Left;
K2-> Left = K1-> Right;
K1-> Right = K2;
 
K2-> Height = Max (HeightAvl (K2-> Left), HeightAvl (K2-> Right) + 1;
K1-> Height = Max (HeightAvl (K1-> Left), HeightAvl (K2-> Right) + 1;
 
Return K1;
}
 
Static Position SingleRotateWithRight (Position K2)
{
Position K1;
 
K1 = K2-> Right;
K2-> Right = K1-> Left;
K1-> Left = K2;
 
K2-> Height = Max (HeightAvl (K2-> Left), HeightAvl (K2-> Right) + 1;
K1-> Height = Max (HeightAvl (K1-> Left), HeightAvl (K2-> Right) + 1;
 
Return K1;
}
 
Static Position DoubleRotateWithLeft (Position K3)
{
K3-> Left = SingleRotateWithRight (K3-> Left );
Return SingleRotateWithLeft (K3 );
}
 
Static Position DoubleRotateWithRight (Position K3)
{
K3-> Left = SingleRotateWithLeft (K3-> Left );
Return SingleRotateWithRight (K3 );
}
 
AvlTree InsertAvl (int X, AvlTree T)
{
If (T = NULL)
{
T = (AvlTree) malloc (sizeof (AvlTree ));
If (T = NULL)
{
Printf ("out of space !!! \ N ");
}
Else
{
T-> Left = NULL;
T-> Right = NULL;
}
T-> Element = X;
T-> Height = 0;
}
Else if (X <T-> Element)
{
T-> Left = InsertAvl (X, T-> Left );
If (HeightAvl (T-> Left)-HeightAvl (T-> Right) = 2)
{
If (X <T-> Left-> Element)
{
T = SingleRotateWithLeft (T );
}
Else
{
T = DoubleRotateWithLeft (T );
}
}
}
Else if (X> T-> Element)
{
T-> Right = InsertAvl (X, T-> Right );
If (HeightAvl (T-> Right)-HeightAvl (T-> Left) = 2)
{
If (X> T-> Right-> Element)
{
T = SingleRotateWithRight (T );
}
Else
{
T = DoubleRotateWithRight (T );
}
}
}
T-> Height = Max (HeightAvl (T-> Left), HeightAvl (T-> Right) + 1;
Return T;
}
 
 
Int main (void)
{
AvlTree;
InsertAvl (1, Tree );
}

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