Remove redundant tree traversals (#4161)

src/main/java/com/thealgorithms/datastructures/trees/LevelOrderTraversal.java

@@ -7,7 +7,7 @@ import java.util.Queue;
 
 public class LevelOrderTraversal {
 
-    static List<List<Integer>> traverse(BinaryTree.Node root) {
+    public static List<List<Integer>> traverse(BinaryTree.Node root) {
         if (root == null) {
             return List.of();
         }
@@ -35,4 +35,18 @@ public class LevelOrderTraversal {
         }
         return result;
     }
+
+    /* Print nodes at the given level */
+    public static void printGivenLevel(BinaryTree.Node root, int level) {
+        if (root == null) {
+            System.out.println("Root node must not be null! Exiting.");
+            return;
+        }
+        if (level == 1) {
+            System.out.print(root.data + " ");
+        } else if (level > 1) {
+            printGivenLevel(root.left, level - 1);
+            printGivenLevel(root.right, level - 1);
+        }
+    }
 }

src/main/java/com/thealgorithms/datastructures/trees/LevelOrderTraversalHelper.java

@@ -1,43 +0,0 @@
-package com.thealgorithms.datastructures.trees;
-
-public class LevelOrderTraversalHelper {
-    /* function to print level order traversal of tree*/
-    public static void printLevelOrder(BinaryTree.Node root) {
-        if (root == null) {
-            System.out.println("Root node must not be null! Exiting.");
-            return;
-        }
-
-        int h = height(root);
-        int i;
-        for (i = 1; i <= h; i++) {
-            printGivenLevel(root, i);
-        }
-    }
-
-    /* Compute the "height" of a tree -- the number of
-  nodes along the longest path from the root node
-  down to the farthest leaf node.*/
-    private static int height(BinaryTree.Node root) {
-        if (root == null) {
-            return 0;
-        } else {
-            //return the height of larger subtree
-            return Math.max(height(root.left), height(root.right)) + 1;
-        }
-    }
-
-    /* Print nodes at the given level */
-    public static void printGivenLevel(BinaryTree.Node root, int level) {
-        if (root == null) {
-            System.out.println("Root node must not be null! Exiting.");
-            return;
-        }
-        if (level == 1) {
-            System.out.print(root.data + " ");
-        } else if (level > 1) {
-            printGivenLevel(root.left, level - 1);
-            printGivenLevel(root.right, level - 1);
-        }
-    }
-}

src/main/java/com/thealgorithms/datastructures/trees/TreeTraversal.java

@@ -1,120 +0,0 @@
-package com.thealgorithms.datastructures.trees;
-
-import java.util.LinkedList;
-
-/**
- * @author Varun Upadhyay (https://github.com/varunu28)
- */
-// Driver Program
-public class TreeTraversal {
-
-    public static void main(String[] args) {
-        Node tree = new Node(5);
-        tree.insert(3);
-        tree.insert(2);
-        tree.insert(7);
-        tree.insert(4);
-        tree.insert(6);
-        tree.insert(8);
-
-        // Prints 5 3 2 4 7 6 8
-        System.out.println("Pre order traversal:");
-        tree.printPreOrder();
-        System.out.println();
-        // Prints 2 3 4 5 6 7 8
-        System.out.println("In order traversal:");
-        tree.printInOrder();
-        System.out.println();
-        // Prints 2 4 3 6 8 7 5
-        System.out.println("Post order traversal:");
-        tree.printPostOrder();
-        System.out.println();
-        // Prints 5 3 7 2 4 6 8
-        System.out.println("Level order traversal:");
-        tree.printLevelOrder();
-        System.out.println();
-    }
-}
-
-/**
- * The Node class which initializes a Node of a tree Consists of all 4 traversal
- * methods: printInOrder, printPostOrder， printPreOrder & printLevelOrder
- * printInOrder: LEFT -> ROOT -> RIGHT printPreOrder: ROOT -> LEFT -> RIGHT
- * printPostOrder: LEFT -> RIGHT -> ROOT printLevelOrder: Prints by level
- * (starting at root), from left to right.
- */
-class Node {
-
-    Node left, right;
-    int data;
-
-    public Node(int data) {
-        this.data = data;
-    }
-
-    public void insert(int value) {
-        if (value < data) {
-            if (left == null) {
-                left = new Node(value);
-            } else {
-                left.insert(value);
-            }
-        } else {
-            if (right == null) {
-                right = new Node(value);
-            } else {
-                right.insert(value);
-            }
-        }
-    }
-
-    public void printInOrder() {
-        if (left != null) {
-            left.printInOrder();
-        }
-        System.out.print(data + " ");
-        if (right != null) {
-            right.printInOrder();
-        }
-    }
-
-    public void printPreOrder() {
-        System.out.print(data + " ");
-        if (left != null) {
-            left.printPreOrder();
-        }
-        if (right != null) {
-            right.printPreOrder();
-        }
-    }
-
-    public void printPostOrder() {
-        if (left != null) {
-            left.printPostOrder();
-        }
-        if (right != null) {
-            right.printPostOrder();
-        }
-        System.out.print(data + " ");
-    }
-
-    /**
-     * O(n) time algorithm. Uses O(n) space to store nodes in a queue to aid in
-     * traversal.
-     */
-    public void printLevelOrder() {
-        LinkedList<Node> queue = new LinkedList<>();
-        queue.add(this);
-        while (queue.size() > 0) {
-            Node head = queue.remove();
-            System.out.print(head.data + " ");
-            // Add children of recently-printed node to queue, if they exist.
-            if (head.left != null) {
-                queue.add(head.left);
-            }
-            if (head.right != null) {
-                queue.add(head.right);
-            }
-        }
-    }
-}