feat(0226): 新增java bfs写法

problems/0226.翻转二叉树.md

@@ -205,6 +205,7 @@ public:
 Java：
 
 ```Java
+//DFS递归
 class Solution {
    /**
      * 前后序遍历都可以
@@ -226,6 +227,31 @@ class Solution {
         root.right = tmp;
     }
 }
+
+//BFS
+class Solution {
+    public TreeNode invertTree(TreeNode root) {
+        if (root == null) {return null;}
+        ArrayDeque<TreeNode> deque = new ArrayDeque<>();
+        deque.offer(root);
+        while (!deque.isEmpty()) {
+            int size = deque.size();
+            while (size-- > 0) {
+                TreeNode node = deque.poll();
+                swap(node);
+                if (node.left != null) {deque.offer(node.left);}
+                if (node.right != null) {deque.offer(node.right);}
+            }
+        }
+        return root;
+    }
+
+    public void swap(TreeNode root) {
+        TreeNode temp = root.left;
+        root.left = root.right;
+        root.right = temp;
+    }
+}
 ```
 
 Python：