add: BinaryTreeSymmetry

Author: Jer3myYu

java/Trees/BinaryTreeSymmetry.java

@@ -0,0 +1,44 @@
+import DS.TreeNode;
+
+/*
+    // Definition of TreeNode:
+    class TreeNode {
+        public int val;
+        public TreeNode left;
+        public TreeNode right;
+        public TreeNode(int val) {
+            this.val = val;
+        }
+    }
+ */
+
+public class BinaryTreeSymmetry {
+    public boolean binaryTreeSymmetry(TreeNode root) {
+        if (root == null) {
+            return true;
+        }
+        return compareTrees(root.left, root.right);
+    }
+
+    private boolean compareTrees(TreeNode node1, TreeNode node2) {
+        // Base case: if both nodes are null, they're symmetric.
+        if (node1 == null && node2 == null) {
+            return true;
+        }
+        // If one node is null and the other isn't, they aren't symmetric.
+        if (node1 == null || node2 == null) {
+            return false;
+        }
+        // If the values of the current nodes don't match, trees aren't symmetric.
+        if (node1.val != node2.val) {
+            return false;
+        }
+        // Compare the 'node1's left subtree with 'node2's right subtree. If these 
+        // aren't symmetric, the whole tree is not symmetric.
+        if (!compareTrees(node1.left, node2.right)) {
+            return false;
+        }
+        // Compare the 'node1's right subtree with 'node2's left subtree. 
+        return compareTrees(node1.right, node2.left);
+    }
+}