Refine

begeekmyfriend · begeekmyfriend · commit 82f53c39c0a6 · 2020-08-07T16:22:40.000+08:00
Signed-off-by: begeekmyfriend &lt;begeekmyfriend@gmail.com&gt;
diff --git a/226_invert_binary_tree/invert_binary_tree.c b/226_invert_binary_tree/invert_binary_tree.c
@@ -10,13 +10,14 @@ struct TreeNode {
 
 static struct TreeNode *invertTree(struct TreeNode* root)
 {
-    if (root != NULL) {
-        struct TreeNode *node = root->left;
-        root->left = root->right;
-        root->right = node;
-        invertTree(root->left);
-        invertTree(root->right);
+    if (root == NULL) {
+        return NULL;
     }
+
+    struct TreeNode *l = invertTree(root->left);
+    struct TreeNode *r = invertTree(root->right);
+    root->left = r;
+    root->right = l;
     return root;
 }
 

Original file line number	Diff line number	Diff line change
`@@ -10,13 +10,14 @@ struct TreeNode {`
`10`	`10`
`11`	`11`	`static struct TreeNode invertTree(struct TreeNode root)`
`12`	`12`	`{`
`13`		`- if (root != NULL) {`
`14`		`- struct TreeNode *node = root->left;`
`15`		`- root->left = root->right;`
`16`		`- root->right = node;`
`17`		`- invertTree(root->left);`
`18`		`- invertTree(root->right);`
	`13`	`+ if (root == NULL) {`
	`14`	`+ return NULL;`
`19`	`15`	`}`
	`16`	`+`
	`17`	`+ struct TreeNode *l = invertTree(root->left);`
	`18`	`+ struct TreeNode *r = invertTree(root->right);`
	`19`	`+ root->left = r;`
	`20`	`+ root->right = l;`
`20`	`21`	`return root;`
`21`	`22`	`}`
`22`	`23`