Fix: remove main method and input for build compliance

Author: konduri-lakshmi-prasanna

src/main/java/com/thealgorithms/backtracking/BinaryTreePaths.java

@@ -1,7 +1,11 @@
 package com.thealgorithms.backtracking;
-import java.util.*;
+
+import java.util.ArrayList;
+import java.util.List;
+
 public class BinaryTreePaths {
-    static class TreeNode {
+
+    public static class TreeNode {
         int val;
         TreeNode left;
         TreeNode right;
@@ -10,18 +14,26 @@ static class TreeNode {
             this.val = val;
         }
     }
+
     public List<String> binaryTreePaths(TreeNode root) {
         List<String> list = new ArrayList<>();
-        if (root == null) return list;
+        if (root == null) {
+            return list;
+        }
         dfs(root, "", list);
         return list;
     }
 
     private void dfs(TreeNode node, String path, List<String> list) {
-        if (node == null) return;
+        if (node == null) {
+            return;
+        }
 
-        if (path.isEmpty()) path = "" + node.val;
-        else path += "->" + node.val;
+        if (path.isEmpty()) {
+            path = Integer.toString(node.val);
+        } else {
+            path += "->" + node.val;
+        }
 
         if (node.left == null && node.right == null) {
             list.add(path);
@@ -31,45 +43,4 @@ private void dfs(TreeNode node, String path, List<String> list) {
         dfs(node.left, path, list);
         dfs(node.right, path, list);
     }
-    private static TreeNode buildTreeFromInput(Scanner sc) {
-        System.out.print("Enter number of nodes: ");
-        int n = sc.nextInt();
-        if (n == 0) return null;
-
-        System.out.println("Enter node values in level order (use -1 for nulls):");
-        int[] values = new int[n];
-        for (int i = 0; i < n; i++) values[i] = sc.nextInt();
-
-        if (values[0] == -1) return null;
-        TreeNode root = new TreeNode(values[0]);
-        Queue<TreeNode> queue = new LinkedList<>();
-        queue.add(root);
-
-        int i = 1;
-        while (i < n && !queue.isEmpty()) {
-            TreeNode current = queue.poll();
-            if (i < n && values[i] != -1) {
-                current.left = new TreeNode(values[i]);
-                queue.add(current.left);
-            }
-            i++;
-            if (i < n && values[i] != -1) {
-                current.right = new TreeNode(values[i]);
-                queue.add(current.right);
-            }
-            i++;
-        }
-        return root;
-    }
-
-    public static void main(String[] args) {
-        Scanner sc = new Scanner(System.in);
-        TreeNode root = buildTreeFromInput(sc);
-
-        BinaryTreePaths solver = new BinaryTreePaths();
-        List<String> result = solver.binaryTreePaths(root);
-
-        System.out.println("All root-to-leaf paths: " + result);
-        sc.close();
-    }
 }