Bottom-View Traversal in binary Tree (code in JAVA)
import java.util.*;
public class test {
static class Node {
int data;
Node left;
Node right;
int hd;
public Node(int data) {
this.data = data;
this.left = null;
this.right = null;
hd = 0;
}
}
static class BinaryTree {
static Node buildTree(Scanner scanner, String position, int parentValue) {
System.out.print("Add " + position + " node for " + parentValue + " (y/n): ");
String userChoice = scanner.next();
if (userChoice.equalsIgnoreCase("y")) {
System.out.print("Enter " + position + " node value: ");
int nodeValue = scanner.nextInt();
Node newNode = new Node(nodeValue);
newNode.left = buildTree(scanner, "left", nodeValue);
newNode.right = buildTree(scanner, "right", nodeValue);
return newNode;
} else {
return null;
}
}
}
//levelorder traversal
public static void levelorder(Node root)
{
if(root==null) return;
Queue<Node> q = new LinkedList<>();
q.add(root);
q.add(null);
while(!q.isEmpty())
{
Node currnode = q.remove();
if(currnode==null) //NULL DENOTES NEW LINE
{
System.out.println();
if(q.isEmpty())
{
break;
}
else
{
q.add(null);
}
}
else
{
System.out.print(currnode.data+" ");
if(currnode.left!=null)
{
q.add(currnode.left);
}
if(currnode.right!=null)
{
q.add(currnode.right);
}
}
}
}
public static ArrayList<Integer> preorderUsingStack(Node root)
{
ArrayList<Integer> preorderArrayList = new ArrayList<Integer>();
if (root==null) return preorderArrayList;
Stack<Node> st = new Stack<Node>();
st.push(root);
while(!st.isEmpty())
{
root = st.pop();
preorderArrayList.add(root.data);
if(root.right != null)
{
st.push(root.right);
}
if(root.left != null)
{
st.push(root.left);
}
}
return preorderArrayList;
}
public static ArrayList<Integer> inorderUsingStack(Node root)
{
ArrayList<Integer> inorderArrayList = new ArrayList<Integer>();
if (root == null) return null;
Stack<Node> st = new Stack<Node>();
Node node = root;
while(true)
{
if(node != null)
{
st.push(node);
node = node.left;
}
else
{
if(st.isEmpty())
{
break;
}
node = st.pop();
inorderArrayList.add(node.data);
node = node.right;
}
}
return inorderArrayList;
}
public static ArrayList<Integer> postorderUsing2Stack(Node root)
{
ArrayList<Integer> postorderArrayList = new ArrayList<Integer>();
if(root == null){return postorderArrayList;}
Stack<Node> st1 = new Stack<Node>();
Stack<Node> st2 = new Stack<Node>();
st1.push(root);
while(!st1.isEmpty())
{
root = st1.pop();
st2.push(root);
if(root.left!=null) st1.push(root.left);
if(root.right!=null) st1.push(root.right);
}
while(!st2.isEmpty())
{
postorderArrayList.add(st2.pop().data);
}
return postorderArrayList;
}
public static ArrayList<Integer> postorderUsing1Stack(Node root) {
ArrayList<Integer> postorderArrayList = new ArrayList<Integer>();
if (root == null) return postorderArrayList;
Stack<Node> st = new Stack<Node>();
Node curr = root;
Node prev = null;
while (curr != null || !st.isEmpty()) {
if (curr != null) {
st.push(curr);
curr = curr.left;
} else {
Node peekNode = st.peek();
if (peekNode.right == null || peekNode.right == prev) { //peekNode is topNode in stack
postorderArrayList.add(peekNode.data);
prev = peekNode;
st.pop();
} else {
curr = peekNode.right;
}
}
}
return postorderArrayList;
}
static class node_numOfTraversal_pair
{
Node node;
int num;
public node_numOfTraversal_pair(Node root, int _num)
{
this.num = _num;
this.node = root;
}
}
public static void preInPost_traversal_in_one(Node root, ArrayList<Integer> preorderArrayList, ArrayList<Integer> inorderArrayList, ArrayList<Integer> postorderArrayList)
{
Stack<node_numOfTraversal_pair> st = new Stack<node_numOfTraversal_pair>();
if(root == null) return;
// or instead of above two lines you can directly write as below
// node_numOfTraversal_pair pair = new node_numOfTraversal_pair(root,1);
// st.push(pair);
st.push(new node_numOfTraversal_pair(root, 1));
while(!st.isEmpty())
{
node_numOfTraversal_pair it = st.pop();
// this is part of pre
// increment 1 to 2
// push the left side of the tree
if(it.num == 1)
{
preorderArrayList.add(it.node.data);
it.num++;
st.push(it);
if(it.node.left != null)
{
st.push(new node_numOfTraversal_pair(it.node.left, 1));
}
}
// this is a part of in
// increment 2 to 3
// push right
else if(it.num == 2)
{
inorderArrayList.add(it.node.data);
it.num++;
st.push(it);
if(it.node.right != null)
{
st.push(new node_numOfTraversal_pair(it.node.right, 1));
}
}
// don't push it back again
else
{
postorderArrayList.add(it.node.data);
}
}
}
public static int maxDepthOfBinaryTree(Node root)
{
if(root == null) return 0;
int leftHeight = maxDepthOfBinaryTree(root.left);
int rightHeight = maxDepthOfBinaryTree(root.right);
return 1 + Math.max(leftHeight,rightHeight);
}
// To check for Balanced Binary Tree
public static int isBalacedBinaryTree(Node root)
{
if(root == null) return 0;
int leftHeight = isBalacedBinaryTree(root.left);
if(leftHeight==-1){return -1;}
int rightHeight = isBalacedBinaryTree(root.right);
if(rightHeight==-1){return -1;}
if(Math.abs(leftHeight-rightHeight)>1){return -1;}
return 1 + Math.max(leftHeight,rightHeight);
}
public static boolean isBalancedBinaryTree_boolean_value(Node root)
{
return isBalacedBinaryTree(root) != -1;
}
// To measure diameter of binary tree
public static int height(Node root, int diameter[])
{
if(root == null) return 0;
int leftHeight = height(root.left,diameter);
int rightHeight = height(root.right,diameter);
diameter[0] = Math.max(diameter[0],leftHeight+rightHeight);
return 1 + Math.max(leftHeight,rightHeight);
}
public static int diameterofbinarytree(Node root)
{
int diameter1[]= new int[1];
height(root,diameter1);
return diameter1[0];
}
// Maximum Path Sum
public static int maxPath(Node node, int maxValue[]) {
if (node == null) return 0;
int left = Math.max(0, maxPath(node.left, maxValue));
int right = Math.max(0, maxPath(node.right, maxValue));
maxValue[0] = Math.max(maxValue[0], left + right + node.data);
return Math.max(left, right) + node.data;
}
public static int maxPathSum(Node root) {
int maxValue[] = new int[1];
maxValue[0] = Integer.MIN_VALUE;
maxPath(root, maxValue);
return maxValue[0];
}
// Zig-zag or spiral traversal
static ArrayList<Integer> zigZagTraversal(Node root)
{
ArrayList<Integer> ans = new ArrayList<Integer>();
if (root == null)
return ans;
Queue<Node> q = new LinkedList<Node>();
q.add(root);
boolean leftToRight = true;
while (q.size() > 0) {
int size = q.size();
ArrayList<Integer> temp = new ArrayList<>();
for (int i = 0; i < size; i++) {
Node curr = q.poll();
if (curr.left != null)
q.add(curr.left);
if (curr.right != null)
q.add(curr.right);
temp.add(curr.data);
}
if (leftToRight)
{
// do nothing
}
else {
Collections.reverse(temp);
}
for (int i = 0; i < temp.size(); i++) {
ans.add(temp.get(i));
}
leftToRight = !(leftToRight);
}
return ans;
}
// boundary traversal
public static void printLeftBoundary(Node node) {
if (node == null)
return;
if (node.left != null) {
System.out.print(node.data + " ");
printLeftBoundary(node.left);
} else if (node.right != null) {
System.out.print(node.data + " ");
printLeftBoundary(node.right);
}
}
public static void printRightBoundary(Node node) {
if (node == null)
return;
if (node.right != null) {
printRightBoundary(node.right);
System.out.print(node.data + " ");
} else if (node.left != null) {
printRightBoundary(node.left);
System.out.print(node.data + " ");
}
}
public static void printLeaves(Node node) {
if (node == null)
return;
printLeaves(node.left);
if (node.left == null && node.right == null)
System.out.print(node.data + " ");
printLeaves(node.right);
}
public static void boundaryTraversal(Node root) {
if (root == null)
return;
System.out.print(root.data + " ");
printLeftBoundary(root.left);
printLeaves(root.left);
printLeaves(root.right);
printRightBoundary(root.right);
}
// Vertical order traversal
public static void verticalOrder(Node root,int horizontal_dist, Map<Integer, Vector<Integer>> m)
{
if (root==null) return;
Vector<Integer> v = m.get(horizontal_dist);
if(v==null)
{
v = new Vector<Integer>();
v.add(root.data);
}
else
{
v.add(root.data);
}
m.put(horizontal_dist,v);
verticalOrder(root.left, horizontal_dist - 1, m);
verticalOrder(root.right, horizontal_dist + 1, m);
}
// Top-view of a binary tree
static class Pair {
Node node;
int hd;
Pair(Node node, int hd) {
this.node = node;
this.hd = hd;
}
}
static ArrayList<Integer> topView(Node root)
{
ArrayList<Integer> ans = new ArrayList<>();
if(root == null) return ans;
Map<Integer, Integer> map = new TreeMap<>();
Queue<Pair> q = new LinkedList<Pair>();
q.add(new Pair(root, 0));
while(!q.isEmpty()) {
Pair it = q.remove();
int hd = it.hd;
Node temp = it.node;
if(map.get(hd) == null) map.put(hd, temp.data);
if(temp.left != null) {
q.add(new Pair(temp.left, hd - 1));
}
if(temp.right != null) {
q.add(new Pair(temp.right, hd + 1));
}
}
for (Map.Entry<Integer,Integer> entry : map.entrySet()) {
ans.add(entry.getValue());
}
return ans;
}
// Bottom-View of Binary Tree
public static ArrayList <Integer> bottomView(Node root)
{
ArrayList<Integer> ans = new ArrayList<>();
if(root == null) return ans;
Map<Integer, Integer> map = new TreeMap<>();
Queue<Node> q = new LinkedList<Node>();
root.hd = 0;
q.add(root);
while(!q.isEmpty()) {
Node temp = q.remove();
int hd = temp.hd;
map.put(hd, temp.data);
if(temp.left != null) {
temp.left.hd = hd - 1;
q.add(temp.left);
}
if(temp.right != null) {
temp.right.hd = hd + 1;
q.add(temp.right);
}
}
for (Map.Entry<Integer,Integer> entry : map.entrySet()) {
ans.add(entry.getValue());
}
return ans;
}
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
BinaryTree bt = new BinaryTree();
System.out.print("Enter root node value: ");
int rootValue = scanner.nextInt();
Node root = new Node(rootValue);
root.left = bt.buildTree(scanner, "left", rootValue);
root.right = bt.buildTree(scanner, "right", rootValue);
System.out.println("Tree construction complete.");
levelorder(root);
System.out.println(preorderUsingStack(root));
System.out.println(inorderUsingStack(root));
System.out.println(postorderUsing2Stack(root));
System.out.println(postorderUsing1Stack(root));
ArrayList<Integer> preorderArrayList = new ArrayList<Integer>();
ArrayList<Integer> inorderArrayList = new ArrayList<Integer>();
ArrayList<Integer> postorderArrayList = new ArrayList<Integer>();
preInPost_traversal_in_one(root, preorderArrayList, inorderArrayList, postorderArrayList);
System.out.print("The preorder traversal is: ");
for (Integer pre : preorderArrayList) {
System.out.print(pre+" ");
}
System.out.println();
System.out.print("The inorder traversal is: ");
for (Integer in : inorderArrayList) {
System.out.print(in+" ");
}
System.out.println();
System.out.print("The postorder traversal is: ");
for (Integer post : postorderArrayList) {
System.out.print(post+" ");
}
System.out.println();
System.out.println("The depth of your tree is: "+maxDepthOfBinaryTree(root));
boolean balanced_var = isBalancedBinaryTree_boolean_value(root);
System.out.println(balanced_var);
System.out.println("The diameter of given binary tree is: "+diameterofbinarytree(root));
System.out.println("The maximum path sum is: "+maxPathSum(root));
System.out.println("The zigZag Traversal is: "+zigZagTraversal(root));
System.out.println("The boundary traversal is as below:");
boundaryTraversal(root);
System.out.println();
System.out.println("The vertical order traversal is as below:");
TreeMap<Integer, Vector<Integer>> m = new TreeMap<>();
int hd = 0;
verticalOrder(root, hd, m);
for (Map.Entry<Integer,Vector<Integer>> e : m.entrySet()) {
System.out.println(e.getValue());
}
System.out.println("Top view traversal is :");
System.out.println(topView(root));
System.out.println("Bottom view traversal is :");
System.out.println(bottomView(root));
scanner.close();
}
}
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