class  Solution{

     public:

         void exchage(TreeNode *root){

             TreeNode* node=root;

             if (node!=NULL){

                 TreeNode* temp=node->left;

                 node ->left=node->right;

                 node->right=temp;

             }

         }

         TreeNode *invertTree(TreeNode *root){

             TreeNode*node=root

             if (root==NULL){

                 return root;

             }

             invertTree(node->left)

             invertTree(node->right)

             exchange(node);

             return root;

         }

 };