code styling and refactoring for algorithms: Bellman-Ford, Dijkstras, ReverseLinkedList, CompareBinaryTree and InvertBinaryTree

DataStructures/CompareBinaryTree/CompareBinaryTree.php

@@ -0,0 +1,35 @@
+<?php
+
+namespace DataStructures\CompareBinaryTree;
+
+/**
+ * Recurrent comparison of binary trees based on comparison of left and right branches
+ * (https://en.wikipedia.org/wiki/Binary_tree).
+ *
+ * @author Michał Żarnecki https://github.com/rzarno
+ */
+class CompareBinaryTree
+{
+    /**
+     * compare two binary trees
+     * @param BinaryTreeNode|null $a
+     * @param BinaryTreeNode|null $b
+     * @return bool
+     */
+    public function areTreesEqual(?BinaryTreeNode $a, ?BinaryTreeNode $b): bool
+    {
+        if (! $a  &&  $b || $a && ! $b) {
+            return false;
+        }
+
+        if (! $a && ! $b) {
+            return true;
+        }
+
+        if ($a->value !== $b->value) {
+            return false;
+        }
+        return  $this->areTreesEqual($a->left, $b->left)
+            &&  $this->areTreesEqual($a->right, $b->right);
+    }
+}