void main()
{
FILE *pipe;
NODE H=NULL;
int n,k,j;
int m=0;
H=Create_Leaf(0,H);
H->left=H->right=H;
printf("\n Enter number of nodes ");
scanf("%d",&n);
OutputFile = fopen ("avltree.dot", "w");
fclose (OutputFile);
for(j=0;j<n;j++)
{
printf("Enter element");
scanf("%d",&k); //redirect from file "avlIP"
H=insert(k,H);
}
OutputFile=fopen("avltree.dot","a");
if(OutputFile != NULL)
{
if(H->left!=NULL)
dotDump(H->left,OutputFile);
else dotDump(H->right,OutputFile);
}
fclose(OutputFile);
pipe=popen("dot -Tps avltree.dot -o avltree.ps","w");
pclose(pipe);
pipe=popen("evince avltree.ps","r");
pclose(pipe);
}
NODE insert(int key,NODE H)
{
NODE NN;
if(H->left==H)
{
NN=Create_Leaf(key,NN);
H->left=NN;
return H;
}
lvl=0;
dir[lvl]='L';
path[lvl]=H;
T=H->left;
while(1)
{
if(key<T->key)
{
if(T->left!=NULL)
{
lvl=lvl+1;
path[lvl]=T;
dir[lvl]='L';
T=T->left;
}
else
{
NN=Create_Leaf(key,NN);
T->left=NN;
lvl=lvl+1;
path[lvl]=T;
dir[lvl]='L';
break;
}
}
else if(key>T->key)
{
if(T->right!=NULL)
{
lvl=lvl+1;
path[lvl]=T;
dir[lvl]='R';
T=T->right;
}
else
{
NN=Create_Leaf(key,NN);
T->right=NN;
lvl=lvl+1;
path[lvl]=T;
dir[lvl]='R';
break;
}
}
else
{
printf("\n Key already exists ");
return H;
}
}
mark=0;
for(i=lvl;i>=1;i--)
{
P=path[i];
if(P->BI!='B')
{
mark=i;
break;
}
}
for(i=mark+1;i<=lvl;i++)
{
if(key<path[i]->key)
{
path[i]->BI='L';
}
else path[i]->BI='R';
}
if(mark==0)
{
return H;
}
D=dir[mark];
X=path[mark];
Y=path[mark+1];
if(X->BI!=D)
{
X->BI='B';
return H;
}
//rebalancing 1
if(Y->BI==D)
{
if(D=='L')
{
X->left=Y->right;
Y->right=X;
}
else
{
X->right=Y->left;
Y->left=X;
}
X->BI=Y->BI='B';
F=path[mark-1];
if(X==F->left)
{
F->left=Y;
}
else F->right=Y;
return H;
}
//rebalancing 2
//changing structure link
if(D=='L')
{
Z=Y->right;
Y->right=Z->left;
Z->left=Y;
X->left=Z->right;
Z->right=X;
}
else
{
Z=Y->left;
Y->left=Z->right;
Z->right=Y;
X->right=Z->left;
Z->left=X;
}
F=path[mark-1];
if(X==F->left)
{
F->left=Z;
}
else F->right=Z;
//changing balance indicators
if(Z->BI==D)
{
Y->BI=Z->BI='B';
if(D=='L')
{
X->BI='R';
}
else X->BI='L';
}
else if(Z->BI=='B')
{
X->BI=Y->BI=Z->BI='B';
}
else
{
X->BI=Z->BI='B';
Y->BI=D;
}
return H;
}
//Program to insert a node into the tree
NODE Insert(int key,NODE H)
{
NODE NN;
if(H->llink==H)
{
NN=Create_Leaf(key,NN);
H->llink=NN;
return H;
}
level=0;
dir[level]='L';
path[level]=H;
t=H->llink;
while(1)
{
//if the key entered is lesser than the present key
if(key<t->key)
{
if(t->llink!=NULL)
{
level=level+1;
path[level]=t;
dir[level]='L';
t=t->llink;
}
else
{
NN=Create_Leaf(key,NN);
t->llink=NN;
level=level+1;
path[level]=t;
dir[level]='L';
break;
}
}
else if(key>t->key)
{
if(t->rlink!=NULL)
{
level=level+1;
path[level]=t;
dir[level]='R';
t=t->rlink;
}
else
{
NN=Create_Leaf(key,NN);
t->rlink=NN;
level=level+1;
path[level]=t;
dir[level]='R';
break;
}
}//if the keys are equal
else
{
key = key + 1;
return H;
}
}
mark=0;
//to maintain the balance factor of the nodes
for(i=level;i>=1;i--)
{
p=path[i];
if(p->BI!='B')
{
mark=1;
break;
}
}
//To maintain the path of the tree
for(i=mark+1;i<=level;i++)
{
if(key<path[i]->key)
{
path[i]->BI='L';
}
else path[i]->BI='R';
}
if(mark==0)
{
return H;
}
d=dir[mark];
x=path[mark];
y=path[mark+1];
if(x->BI!=d)
{
x->BI='B';
return H;
}
if(y->BI==d)
{
if(d=='L')
{
x->llink=y->rlink;
y->rlink=x;
}
else
{
x->rlink=y->llink;
y->llink=x;
}
x->BI=y->BI='B';
f=path[mark-1];
if(x==f->llink)
{
f->llink=y;
}
else f->rlink=y;
return H;
}
if(d=='L')
{
z=y->rlink;
y->rlink=z->llink;
z->llink=y;
x->llink=z->rlink;
z->rlink=x;
}
else
{
z=y->llink;
y->llink=z->rlink;
z->rlink=y;
x->rlink=z->llink;
z->llink=x;
}
f=path[mark-1];
if(x==f->llink)
{
f->llink=z;
}
else f->rlink=z;
if(z->BI==d)
{
y->BI=z->BI='B';
if(d=='L')
{
x->BI='R';
}
else x->BI='L';
}
else
{
if(z->BI=='B')
{
x->BI=y->BI=z->BI='B';
}
else
{
x->BI=z->BI='B';
y->BI=d;
}
}
return H;
}
//Program to create a header node
NODE Create_Head(int key,NODE H)
{
H=Create_Leaf(0,H);
H->llink=H->rlink=H;
return H;
}
