Level wise Tree Traversal

README.md

@@ -2184,12 +2184,15 @@ more details.
 -   [*Preorder and Postoder
     Traversals*](https://www.geeksforgeeks.org/618/)
 
--   [*Level order
-    traversal*](https://www.geeksforgeeks.org/level-order-tree-traversal/)
+-   [*Level order traversal*](https://www.geeksforgeeks.org/level-order-tree-traversal/)
+    - [Source Code](res/Tree/levelWiseTreeTraversal.cpp)
+
 
 -   [*Height of Binary
     Tree*](https://www.geeksforgeeks.org/write-a-c-program-to-find-the-maximum-depth-or-height-of-a-tree/)
 
+-   [*Least Common Ancestor in BST*](res/BST/leastCommonAncestor.cpp)
+
 
 **Binary Heaps**
 

res/Binary Search Tree/leastCommonAncestor.cpp

@@ -0,0 +1,64 @@
+/*
+	A program to find the least common ancestor of two nodes in BST
+	Time Complexity : O(logn) where n is size of tree
+
+	Algorithm : As BST follows a specific order where each of the value in right subtree is more than parent node and left sub tree is smaller than parent node
+	So the concept here used is whenever there is an divergence of value the given node is Least Common Ancestor.
+	Before that all are common ancestor. 
+*/
+
+#include<bits/stdc++.h>
+
+using namespace std;
+
+typedef struct bstnode{
+	bstnode *lchild;
+	int data;
+	bstnode *rchild;
+}*bstptr;
+
+void insert(bstptr &T,int n)
+{
+	if(T==NULL)
+	{
+		T=new(bstnode);
+		T->data=n;
+		T->lchild=NULL;
+		T->rchild=NULL;
+	}
+	else
+	{
+		if(T->data>n)
+		insert(T->lchild,n);
+		else
+		insert(T->rchild,n);
+	}
+}
+
+int searchLCA(bstptr B,int m,int M)
+{
+	if(n<B->data && b>B->data)
+	return B->data;
+	if(B->data>n)
+	searchLCA(B->lchild,n,b);
+	else if(B->data < n)
+	searchLCA(B->rchild,n,b);
+}
+
+int main()
+{
+	bstptr T;
+	T=new(bstnode);
+	T=NULL;
+	int n;
+	cin>>n;
+	while(n!=-1)
+	{
+		insert(T,n);
+		cin>>n;
+	}
+	int a,b,m,M;
+	cin>>a>>b;	
+	m = min(a,b), M = max(a,b);
+	cout<<searchLCA(T,m,M);
+}

res/Tree/levelWiseTreeTraversal.cpp

@@ -0,0 +1,88 @@
+/*
+	Given a tree like this
+	          A
+	        /   \
+	       B     C
+	      / \   / \
+	     F  G  H   I
+	    /       \
+	   J         K
+
+	Level Printing:
+	A
+	B C
+	F G H I
+	J K
+*/
+
+
+#include<bits/stdc++.h>
+
+using namespace std;
+
+typedef struct Btnode{
+	Btnode *left_child;
+	char data;
+	Btnode *right_child;
+}*BT_ptr;
+
+void insert(BT_ptr &T,char n)
+{
+	if(T==NULL)
+	{
+		T = new Btnode;
+		T->data = n;
+		T->left_child = NULL;
+		T->right_child = NULL;
+	}
+	char ch;
+	cout<<"Enter left child for "<<n<<" (. if none): ";
+	cin>>ch;
+	if(ch!='.')
+		insert(T->left_child,ch);
+	cout<<"Enter right child for "<<n<<" (. if none) :";
+	cin>>ch;
+	if(ch!='.')	
+		insert(T->right_child,ch);
+	else return;
+}
+
+queue<BT_ptr>q;
+void levelPrint(BT_ptr T)
+{
+	BT_ptr temp = new Btnode;
+	temp->data = '#';
+	temp->left_child = NULL;
+	temp->right_child = NULL;
+	q.push(T);
+	q.push(temp);
+	while(q.size()!=1)
+	{
+		BT_ptr t = q.front();
+		q.pop();
+		if(t->data=='#')
+		{
+			cout<<"\n";
+			q.push(temp);
+		}
+		else
+		{
+			cout<<t->data<<" ";
+			if(t->left_child!=NULL)
+				q.push(t->left_child);
+			if(t->right_child!=NULL)
+				q.push(t->right_child);
+		}
+	}
+}
+
+int main()
+{
+	BT_ptr T = NULL;
+	char ch;
+	cin>>ch;
+	insert(T,ch);
+	levelPrint(T);
+}
+
+