gistfile1.txt

// Mahe Iram Khan
// 18 COB 058
// GI 2028
// Cousins of a node in a given binary tree
// Cousins are defined as children of a sibling node

#include <bits/stdc++.h>
using namespace std;

// Node struct
struct Node
{
	int data;
	Node *left, *right;
};

// newnode function
Node *newNode(int newitem)
{
	Node *temp = new Node;
	temp->data = newitem;
	temp->left = temp->right = NULL;
	return temp;
}

// function to determine level of a node
int Level(Node *root, Node *node, int level)
{
	
	// base cases
	if (root == NULL)
		return 0;
	if (root == node)
		return level;

	// node in left subtree
	int downlevel = Level(root->left, node, level + 1);
	if (downlevel != 0)
		return downlevel;

	// node not in left subtree
	return Level(root->right, node, level + 1);
}

//print node, not sibling 
void printLevel(Node* root, Node *node, int level)
{
	if (root == NULL || level < 2)
		return;
	if (level == 2)
	{
		if (root->left == node || root->right == node)
			return;
		if (root->left)
			cout << root->left->data << " ";
		if (root->right)
			cout << root->right->data;
	}
	else if (level > 2)
	{
		printLevel(root->left, node, level - 1);
		printLevel(root->right, node, level - 1);
	}
}

// print cousins
void printCousins(Node *root, Node *node)
{
	int level = Level(root, node, 1);
	printLevel(root, node, level);
}

int main()
{	int size;
	cout<< "Enter number of nodes in tree.";
	cin>>size;
	cout<<"Enter the nodes of the tree. Press enter between two nodes.";
	vector<int> input(size);
	for(int i=0;i<size;i++){
	int val;
	cin>>val;
	input.push_back(val);
	}
	Node *root = newNode(input[1]);
	root->left = newNode(input[2]);
	root->right = newNode(input[3]);
	root->left->left = newNode(input[4]);
	root->left->right = newNode(input[5]);
	root->left->right->right = newNode(input[6]);
	root->right->left = newNode(input[7]);
	root->right->right = newNode(input[8]);
	root->right->left->right = newNode(input[9]);

	printCousins(root, root->left->right);

	return 0;
}