AVL Tree implementation in C++ (#2679)

AVL_Tree/AVL_Tree.cpp

@@ -0,0 +1,202 @@
+#include<iostream>
+using namespace std;
+
+struct tnode
+{
+    int data;
+    tnode * L, * R;
+    tnode()
+    {
+        L = R = NULL;
+    }
+};
+
+class AVL
+{
+    private:
+        tnode * root;
+    public:
+        AVL() { root = NULL; }
+        tnode * LL(tnode *);
+        tnode * RR(tnode *);
+        tnode * LR(tnode *);
+        tnode * RL(tnode *);
+
+        int height(tnode *);
+        int MAX(int, int);
+
+        void create();
+        tnode * insert(tnode *, int);
+        void display();
+        void inorder(tnode *);
+        void preorder(tnode *);
+};
+
+tnode * AVL :: LL(tnode * parent)
+{
+    tnode * temp;
+    temp = parent -> L;
+    parent -> L = temp -> R;
+    temp -> R = parent;
+    return temp;
+}
+
+tnode * AVL :: RR(tnode * parent)
+{
+    tnode * temp;
+    temp = parent -> R;
+    parent -> R = temp -> L;
+    temp -> L = parent;
+    return temp;
+}
+
+tnode * AVL :: LR(tnode * parent)
+{
+    parent -> L = RR(parent -> L);
+    parent = LL(parent);
+    return parent;
+}
+
+tnode * AVL :: RL(tnode * parent)
+{
+    parent -> R = LL(parent -> R);
+    parent = RR(parent);
+    return parent;
+}
+
+int AVL :: MAX(int a, int b)
+{
+    if(a > b)
+        return a;
+    else
+        return b;
+}
+
+int AVL :: height(tnode * temp )
+{
+    if(temp == NULL)                                    //height of empty node(subtree)
+        return -1;
+
+    if(temp -> L == NULL and temp -> R == NULL)             //height of leaf node
+        return 0;
+
+    return (1 + MAX( height(temp -> L), height(temp -> R)));
+}
+
+void AVL :: create()
+{
+    int val;
+    char ch;
+    do
+    {
+        cout << "Enter Number : ";
+        cin >> val;
+        root = insert(root, val);
+        cout << "Continue : ";
+        cin >> ch;
+    }while(ch == 'y');
+}
+
+tnode * AVL :: insert(tnode * temp, int val)
+{
+    if(temp == NULL)
+    {
+        temp = new tnode;
+        temp -> data = val;
+    }
+    else
+    {
+        if(val < temp -> data)
+        {
+            temp -> L = insert(temp -> L, val);
+            if( ( height(temp -> L) - height(temp -> R) == 2 ) )
+            {
+                if(val < temp -> L -> data)
+                    temp = LL(temp);
+                else
+                    temp = LR(temp);
+            }
+	}
+	else
+	{
+            temp -> R = insert(temp -> R, val);
+            if( ( height(temp -> L) - height(temp -> R)== -2 ) )
+            {
+                if(val > temp -> R -> data)
+                    temp = RR(temp);
+                else
+                    temp = RL(temp);
+            }
+	}
+    }
+    return temp;
+}
+
+void AVL :: inorder(tnode * temp)
+{
+    if(temp != NULL)
+    {
+        inorder(temp -> L);
+        cout << "\n" << temp -> data;
+        inorder(temp -> R);
+    }
+}
+
+void AVL :: preorder(tnode * temp)
+{
+    if(temp != NULL)
+    {
+        cout << "\n"<<temp -> data;
+        preorder(temp -> L);
+        preorder(temp -> R);
+    }
+}
+
+void AVL :: display()
+{
+    cout << "\n Data in Sorted way : ";
+    inorder(root);
+    cout << "\n Preorder : ";
+    preorder(root);
+}
+
+int main()
+{
+    AVL t;
+    t.create();
+    t.display();
+    cout << endl;
+    return 0;
+}
+
+/*
+ Initially putting data in increasing order to form right skewed tree
+ 
+Enter Number : 5
+Continue : y
+Enter Number : 6
+Continue : y
+Enter Number : 7
+Continue : y
+Enter Number : 8
+Continue : y
+Enter Number : 9
+Continue : y
+Enter Number : 10
+Continue : n
+ 
+ Data in Sorted way : 
+5
+6
+7
+8
+9
+10
+ Preorder : 
+8
+6
+5
+7
+9
+10 
+ */