given a binary tree and two nodes, how do you check if there exist a path between them from the root

Do a preorder traversal

if you find anyone of the node then find the other node in the subtree whose root is the first found node.

	bool isPresent(node* node,int n){
	if(node==NULL)
	return false;
	if(node->data==n)
	return true;
	return isPresent(node->left,n)||isPresent(node->right,n);
	}
	bool isBothNodesinSamePathFromRoot(node* node,int n1,int n2){
	if(node==NULL)
	return false;
	if(node->data==n1)
	return isPresent(node,n2);
	if(node->data==n2)
	return isPresent(node,n1);
	return isBothNodesinSamePathFromRoot(node->left,n1,n2)||isBothNodesinSamePathFromRoot(node->right,n1,n2);
	}

view raw isBothNodesinSamePathFromRoot.cpp hosted with ❤ by GitHub

Maximum complete level of a binary tree

Given a binary tree, find the maximum level at which tree is completely filled.

	int getMaxCompleteLevel(node* node){
	if(node==NULL||!(node->left)||!(node->right))
	return 0;
	int l=getMaxCompleteLevel(node->left);
	int r=getMaxCompleteLevel(node->right);
	return 1+min(l,r);
	}

view raw getMaxCompleteLevel.cpp hosted with ❤ by GitHub

Printing nodes at the K distance from root of a binary Tree

Here is a recursive solution.The code is self explanatory

[gist https://gist.github.com/vishnujayvel/5871650]

Printing nodes at the K distance from root of a binary Tree

Here is a recursive solution.The code is self explanatory

[gist https://gist.github.com/vishnujayvel/5871650]