fd

Author: dingjikerbo

leetcode/solution/src/SymmetricTree.java

@@ -49,6 +49,30 @@ public boolean isSymmetric2(TreeNode root) {
         return queue1.isEmpty() && queue2.isEmpty();
     }
 
+    public boolean isSymmetri3(TreeNode root) {
+        Queue<TreeNode> queue = new LinkedList<>();
+        queue.offer(root);
+        queue.offer(root);
+        while (!queue.isEmpty()) {
+            TreeNode left = queue.poll();
+            TreeNode right = queue.poll();
+            if (left == null && right == null) {
+                continue;
+            }
+            if (left == null || right == null) {
+                return false;
+            }
+            if (left.val != right.val) {
+                return false;
+            }
+            queue.offer(left.left);
+            queue.offer(right.right);
+            queue.offer(left.right);
+            queue.offer(right.left);
+        }
+        return true;
+    }
+
     /**
      * 非递归写法
      */