Easy Python Solution
Code
# Code
```python3 []
class Solution:
    def findPoisonedDuration(self, timeSeries: List[int], duration: int) -> int:
        res = duration

        for i in range(1, len(timeSeries)):
            # no overlap
            if timeSeries[i] > timeSeries[i-1] + duration - 1:
                res += duration

            # yes overlap
            else:
                res += timeSeries[i] - timeSeries[i-1]

        return res
```
['Python3']