#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;
}