636 Exclusive Time of Functions - rewrote

class Log { public: int id; string flag; int time; Log(int _id, string _flag, int _time); }; Log::Log(int _id, string _flag, int _time){ id = _id; flag = _flag; time = _time; } class Solution { public: vector<int> exclusiveTime(int n, vector<string>& logs) { vector<int> ans(n); // initialize a vector of answers stack<Log> s; for (const string &log : logs) { stringstream ss(log); string temp1, temp2, temp3; getline(ss, temp1, ':'); getline(ss, temp2, ':'); getline(ss, temp3, ':'); Log curr = Log(stoi(temp1), temp2, stoi(temp3)); if (s.empty()) { s.push(curr); continue; } Log prev = s.top(); // only two cases: 1) switch to a new process, or 2) end the current process // 1) happens when : curr_flag = "start" // 2) happends when : curr_flat = "end" if (curr.flag == "start") { // hold the previous process, and add time to it's answer int pos = prev.id; int delta = curr.time - prev.time; ans[pos] += delta; s.push(curr); } else { // end this process int pos = prev.id; int delta = curr.time - prev.time + 1; ans[pos] += delta; // remove from stack s.pop(); // if there is a process in stack, set it running at the next time stamp if (!s.empty()) s.top().time = curr.time + 1; } } return ans; } };