Print Left View of Binary Tree

package org.wesome.dsalgo;

import lombok.Data;

import java.util.LinkedList;
import java.util.Objects;
import java.util.Queue;

@Data
class Node {
    int data;
    int hrzDis;
    Node left, right;

    public Node(int data) {
        this.data = data;
        left = right = null;
    }
}

public class BinarySearchTree {
    Node root;

    public static void leftView(Node root) {
        if (Objects.isNull(root)) {
            return;
        }
        Queue<Node> queue = new LinkedList<>();
        queue.add(root);
        while (!queue.isEmpty()) {
            int size = queue.size();
            for (int i = 1; i <= size; i++) {
                Node node = queue.poll();
                if (i == 1) {
                    System.out.print(node.data + " ");
                }
                if (Objects.nonNull(node.left)) {
                    queue.add(node.left);
                }
                if (Objects.nonNull(node.right)) {
                    queue.add(node.right);
                }
            }
        }
    }

    void insert(int data) {
        System.out.println("BinarySearchTree.insert data = " + data);
        root = insert(root, data);
    }

    Node insert(Node root, int data) {
        if (Objects.isNull(root)) {
            Node tempNode = new Node(data);
            return tempNode;
        }
        if (data > root.data) {
            root.right = insert(root.right, data);
        } else {
            root.left = insert(root.left, data);
        }
        return root;
    }
}
package org.wesome.dsalgo;

import org.junit.jupiter.api.Test;

public class BinarySearchTreeTest {
    @Test
    void bottomViewTest() {
        BinarySearchTree binarySearchTree = new BinarySearchTree();
        binarySearchTree.insert(4);
        binarySearchTree.insert(2);
        binarySearchTree.insert(1);
        binarySearchTree.insert(3);
        binarySearchTree.insert(6);
        binarySearchTree.insert(5);
        binarySearchTree.insert(7);
        binarySearchTree.insert(7);
        binarySearchTree.leftView(binarySearchTree.root);
    }
}
plugins {
    id 'java'
    id "io.freefair.lombok" version "6.2.0"
}

group = 'org.wesome'
version = '0.0.1-SNAPSHOT'
sourceCompatibility = JavaVersion.VERSION_1_8

configurations {
    compileOnly {
        extendsFrom annotationProcessor
    }
}

repositories {
    mavenCentral()
}

dependencies {
    testImplementation 'org.junit.jupiter:junit-jupiter:5.6.2'
}

test {
    useJUnitPlatform()
}

 

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