@@ -246,4 +246,48 @@ int sumOfLeftLeaves(struct TreeNode* root) {
246246
247247<!-- tabs:end -->
248248
249+ ### Solution 2
250+
251+ <!-- tabs:start -->
252+
253+ ```cpp
254+ /**
255+ * Definition for a binary tree node.
256+ * struct TreeNode {
257+ * int val;
258+ * TreeNode *left;
259+ * TreeNode *right;
260+ * TreeNode() : val(0), left(nullptr), right(nullptr) {}
261+ * TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
262+ * TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
263+ * };
264+ */
265+ class Solution {
266+ public:
267+ int sumOfLeftLeaves(TreeNode* root) {
268+ if (!root) {
269+ return 0;
270+ }
271+ int ans = 0;
272+ stack<TreeNode*> stk{{root}};
273+ while (!stk.empty()) {
274+ root = stk.top(), stk.pop();
275+ if (root->left) {
276+ if (!root->left->left && !root->left->right) {
277+ ans += root->left->val;
278+ } else {
279+ stk.push(root->left);
280+ }
281+ }
282+ if (root->right) {
283+ stk.push(root->right);
284+ }
285+ }
286+ return ans;
287+ }
288+ };
289+ ```
290+ 291+ <!-- tabs:end -->
292+ 249293<!-- end -->
0 commit comments