对称的二叉树

src/offer/Question28.java

@@ -0,0 +1,34 @@
+package offer;
+
+import leecode.tree.TreeNode;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Objects;
+import java.util.Stack;
+
+/**
+ * 对称的二叉树
+ */
+public class Question28 {
+    public boolean isSymmetry(TreeNode node) {
+        TreeNode lHead = new TreeNode(0);
+        lHead.left = node;
+        TreeNode rHead = new TreeNode(0);
+        rHead.left = node;
+        return dfs(lHead.left, rHead.left);
+    }
+
+    private boolean dfs(TreeNode lHead, TreeNode rHead) {
+        if (lHead == null && rHead == null) {
+            return true;
+        }
+        if (lHead == null || rHead == null) {
+            return false;
+        }
+        if (!Objects.equals(lHead.val, rHead.val)) {
+            return false;
+        }
+        return dfs(lHead.left, rHead.right) && dfs(lHead.right, rHead.left);
+    }
+}