Question

Could you please write the algorithms for In-order, Post-order and Level-order in this form as Pre-order is.

void preorder (BinNode rt) if (rt-null) return; // Empty subtree - do nothing visit(rt); preorder (rt.left()); // Process аїї nodes in ïeft preorder (rt.right // Process root node ()); // Process аїї nodes in right

Thank you.

Answer 1

/* rt is the root of the tree */

void postorder(BinNode rt)

{

if(root==NULL) return; // Base Case. Do nothing if root is empty tree.

postorder(rt->left()); // Process all nodes in left.

postorder(rt->right()); // Process all nodes in right.

visit(rt); // Visit root at last.

}

void Inorder(BinNode rt)

{

if(root==NULL) return; // Base Case. Do nothing if root is empty tree.

Inorder(rt->left()); // Process all nodes in left.

visit(rt); // Visit root node.

Inorder(rt->right()); // Process all nodes in right.

}

void Levelorder(BinNode rt)

{

Queue q; // Make a Queue.

q.push(rt->data) // Process root data and push it into queue.Enqueue root.

while(q.size()!=0){

Dequeue and print rt; //remove the first node in queue in FIFO.

Enqueue(rt->left); //add left child of root.

Enqueue(rt->right); //add right child of root.

}

}

/* I have mentioned the best way to print level order.There is one more way for the same.if you want that please comment.*/

/The function below iteratively calls the printLevel function and provides a level in each call. */

void Levelorder(BinNode rt)
{

int h = height(rt);
for (int i=1; i<=h; i++)

{

printLevel(rt, i);

}

}

/*The function below prints nodes on a level of a binary tree revursively. */

void printLevel(BinNode rt, int level)
{

if (rt == NULL) return;

if (level == 1) print(rt);

else if (level > 1)

{

printLevel(rt->left, level-1); /*recurse down on left subtree till level becomes 1*/

printLevel(rt->right, level-1); /*recurse down right subtree till level becomes 1*/

}
}