func findPoisonedDuration(timeSeries []int, duration int) (sum int) {
	n := len(timeSeries)
	if n == 0 {
		return
	}
	for i := 1; i < n; i++ {
		gap := timeSeries[i] - timeSeries[i-1]
		if duration <= gap {
			sum += duration
		} else {
			sum += gap
		}
	}
	sum += duration
	return
}