1
class Solution {
2
 public:
3
  bool isValidSerialization(string preorder) {
4
    stringstream s(preorder);
5
    string str;
6
    int slots = 1;
7
    while (getline(s, str, ',')) {
8
      if (slots == 0) return 0;
9
      if (str == "#")
10
        slots--;
11
      else
12
        slots++;
13
    }
14
    return slots == 0;
15
  }
16
};