636.cpp

// singleScan-iteration.cpp
class Solution {
public:
  vector<int> exclusiveTime(int n, vector<string> &logs) {
    vector<int> res(n, 0);
    int lastTime = 0, lastId = 0;
    vector<int> st(1, 0);
    for (auto &str : logs) {
      int first = str.find(':'), second = str.rfind(':');
      int id = stoi(str.substr(0, first));
      bool end = second - first == 4; // sizeof(":end:")-1;
      int timestamp = stoi(str.substr(second + 1));
      if (end) {
        res[id] += timestamp - lastTime + 1;
        lastTime = timestamp + 1;
        st.pop_back();
      } else {
        res[st.back()] += timestamp - lastTime;
        lastTime = timestamp;
        st.push_back(id);
      }
    }
    return res;
  }
};