Add invert binary tree Solution

Author: s0ooo0k

invert-binary-tree/s0ooo0k.java

@@ -0,0 +1,14 @@
+class Solution {
+    public TreeNode invertTree(TreeNode root) {
+        if(root==null) return null;
+
+        TreeNode left = invertTree(root.left);
+        TreeNode right = invertTree(root.right);
+
+        root.left=right;
+        root.right=left;
+
+        return root;
+    }
+}
+