left view java

// http://code2begin.blogspot.com
// program to print left view of a given binary tree

/**
 * Created by MOHIT on 25-05-2018.
 */

import java.io.*;
import java.util.*;
import static java.lang.Integer.max;


// node class
class node{
    int data;
    node left;
    node right;

    // function that returns a pointer to new node
    public node(int element){
        this.data = element;
        this.left = null;
        this.right = null;

    }
};


public class BinaryTree {

    static int max_level = -1;

    // function to print the left view of the binary tree
    static void left_view(node Node, int level){

        if (Node == null)
            return;

        if (max_level < level){
            max_level = level;
            System.out.print(Node.data + " ");
        }
        left_view(Node.left, level+1);
        left_view(Node.right, level+1);
    }


    public static void main(String arg[]) {
        node head = new node(1);
        head.left = new node(2);
        head.right = new node(3);
        head.left.left = new node(4);
        head.left.right = new node(5);
        head.right.right = new node(6);
        head.left.left.right = new node(7);
        head.right.right.left = new node(8);
        head.left.left.right.left = new node(9);
        head.left.left.right.left.left = new node(10);
        head.right.right.left.right = new node(11);
        head.hd = 0;

        System.out.print("Left view of the binary tree is : ");
        left_view(head, 0);

    }
}