s0404

src/s0404_sum_of_left_leaves.cpp

@@ -0,0 +1,27 @@
+#include "s0404_sum_of_left_leaves.hpp"
+
+struct TreeNodeState_S0404 {
+  TreeNode* ptr;
+  int sum;
+  bool isLeft;
+};
+
+int S0404::sumOfLeftLeaves(TreeNode* root) {
+  int sum{0};
+  queue<TreeNodeState_S0404> q;
+  if (root) q.push(TreeNodeState_S0404{root, root->val, false});
+  while (!q.empty()) {
+    TreeNodeState_S0404 front = q.front();
+    q.pop();
+    if (front.ptr->left == nullptr && front.ptr->right == nullptr &&
+        front.isLeft)
+      sum += front.ptr->val;
+    if (front.ptr->left)
+      q.push(TreeNodeState_S0404{front.ptr->left, front.sum + front.ptr->left->val,
+                           true});
+    if (front.ptr->right)
+      q.push(TreeNodeState_S0404{front.ptr->right, front.sum + front.ptr->right->val,
+                           false});
+  }
+  return sum;
+}