495. Teemo Attacking

https://leetcode.com/problems/teemo-attacking/description/
    int findPoisonedDuration(vector<int>& timeSeries, int duration) {
        if(timeSeries.size() == 0) return 0;
        int res = 0, next = timeSeries[0];
        for(int n: timeSeries) {
            if(n+duration-1 >= next) {
                if(n <= next) res += n + duration - next;
                else res += duration;
                next = n + duration;
            }
        }
        return res;
    }