Splay Tree data structure in C++.

Splay.cpp

@@ -0,0 +1,139 @@
+#include<bits/stdc++.h>
+using namespace std;
+//Create a node class that consists of data value of the node and two child(left and right);
+struct Node
+{
+	int data;
+	struct Node *left, *right;
+};
+//Create a constructer 
+Node* getNode(int val)
+{
+	Node* temp = new Node;
+	temp->data = val;
+	temp->left = NULL;
+	temp->right = NULL;
+	return temp;
+}
+//insert a new value in the tree;
+Node* insert(Node* root, int val)
+{
+	//if root is null then create a new node;
+	if(!root)
+		return getNode(val);
+	if(root->data > val)
+		root->left = insert(root->left, val);	//if the key value is less root then go for left child of root;
+	else
+		root->right = insert(root->right, val);	//else go for right child of the root;
+	return root;		//return root node;
+}
+/**
+left rotation 			a                       b
+					  /   \                   /   \
+					 b     c    ------>      d     a
+				    / \   / \                     / \
+				   d   e f   g                   e   c
+				                                    / \
+				                                   f   g
+**/
+Node* leftRotate(Node* root)
+{
+	Node* temp = root->right;
+	root->right = temp->left;
+	temp->left = root;
+	return temp;
+}
+/**
+right rotation 			a                       c
+					  /   \                   /   \
+					 b     c    ------>      a     g
+				    / \   / \               / \
+				   d   e f   g             b   f
+				                          / \
+				                         d   e
+**/
+Node* rightRotate(Node* root)
+{
+	Node* temp = root->left;
+	root->left = temp->right;
+	temp->right = root;
+	return temp;
+}
+Node* splay(Node* root, int val)
+{
+	//if root is null or root value is equal to key value then return root;
+	if(root == NULL or root->data == val)
+		return root;
+	if(root->data > val)
+	{
+		if(root->left == NULL)
+			return root;		//if root->left is null then return root;
+		if(root->left->data > val)
+		{
+			//if key value less than root->left data then go for root->left->left;
+			root->left->left = splay(root->left->left, val);
+			root = rightRotate(root);	//right rotate;			
+		}
+		else if(root->left->data < val)
+		{
+			//if key value greater than root->left data then go for root->left->right;
+			root->left->right = splay(root->left->right, val);
+			if(root->left->right != NULL)
+				root->left = leftRotate(root->left);	//if root->left->right is not null then left rotate;
+		}
+		return (root->left == NULL) ? root : rightRotate(root);	//if root->left is not null then right rotate;
+	}
+	else
+	{
+		if(root->right == NULL)
+			return root;		//if root->right is null then return root;
+		if(root->right->data > val)
+		{
+			//if key value less than root->right data then go for root->right->left;
+			root->right->left = splay(root->right->left, val);
+			if(root->right->left != NULL)
+				root->right = rightRotate(root->right);		//if root->left->left is not null then right rotate;
+		}
+		else if(root->right->data < val)
+		{
+			//if key value greater than root->right data then go for root->right->right;
+			root->right->right = splay(root->right->right, val);
+			root = leftRotate(root);		//left rotate;
+		}
+		return (root->right == NULL) ? root : leftRotate(root);	//if root->right is not null then left rotate;
+	}
+}
+//search the key value in the tree;
+Node* search(Node* root, int val)
+{
+	return splay(root, val);	//re-arrange the tree according to key value;
+}
+//pre-order traversal in the tree;
+void preorder(Node* root)
+{
+	if(!root)
+		return;	//if root is null then return;
+	cout << root->data << " ";
+	preorder(root->left);
+	preorder(root->right);
+}
+int main()
+{
+	Node* root = NULL;
+	root = insert(root, 50);
+	root = insert(root, 25);
+	root = insert(root, 32);
+	root = insert(root, 62);
+	root = insert(root, 28);
+	root = insert(root, 10);
+	root = insert(root, 70);
+	//pre-order traversal;
+	preorder(root);
+	cout << endl;
+	//search for a element in the tree;
+	root = search(root, 28);
+	//pre-order traversal;
+	preorder(root);
+	cout << endl;
+	return 0;
+}