LeeCode Invert Binary Tree

/**
* Definition for a binary tree node.
* struct TreeNode {
*     int val;
*     struct TreeNode *left;
*     struct TreeNode *right;
* };
*/
struct TreeNode* invertTree(struct TreeNode* root) {
struct TreeNode* temp;
if(root==NULL) return NULL;
else{
invertTree(root->left);
invertTree(root->right);
temp=root->left;
root->left= root->right;
root->right = temp;
return root;
}
}

struct TreeNode* invertTree(struct TreeNode* root) {
struct TreeNode* temp;
if(root==NULL) retrun NULL;
else{
invertTree(root->left);
invertTree(root->right);
temp=root->left;
root->left=root->right;
root->right=temp;
return root;
}
}