Add 129 in c language

c/129-sum-root-to-leaf.c

@@ -0,0 +1,22 @@
+/*
+Return the total sum of all root-to-leaf numbers.
+
+Space: O(1)
+Time: O(n)
+*/
+
+int dfs(struct TreeNode* r, int acc) {
+ if (r==NULL)
+ return acc;
+ if (r->left==NULL && r->right==NULL)
+ return acc*10 + r->val;
+ if (r->left==NULL)
+ return dfs(r->right, acc*10 + r->val);
+ if (r->right==NULL)
+ return dfs(r->left, acc*10 + r->val);
+ return dfs(r->right, acc*10 + r->val) + dfs(r->left, acc*10 + r->val);
+}
+
+int sumNumbers(struct TreeNode* root){
+ return dfs(root, 0);
+}