class ExclusiveTimeFunctions {

//O(n) time and O(n) space

public int[] exclusiveTime(int n, List<String> logs) {

if (n <= 0 || logs == null || logs.isEmpty()) {

return new int[0];

}

int[] result = new int[n];

Deque<int[]> stack = new ArrayDeque<>();

for (String log : logs) {

String[] secs = log.split(":");

int funcId = Integer.parseInt(secs[0]);

int timestamp = Integer.parseInt(secs[2]);

if (secs[1].equals("start")) {

stack.push(new int[]{funcId, timestamp, 0});

} else {

int[] prev = stack.pop();

int totalTime = timestamp - prev[1] + 1;

int execTime = totalTime - prev[2];

if (!stack.isEmpty()) {

(stack.peek())[2] += totalTime;

}

result[funcId] += execTime;

}

}

return result;

}

}