636. Exclusive Time of Functions

每次都把区间放进去， 要是碰到end，就结束上一个start的区间

 

class Solution {
    public int[] exclusiveTime(int n, List<String> logs) {
        if(logs.size() == 0) return new int[0];
        int[] res = new int[n];
        Stack<Integer> stack = new Stack<>();
        int prev = 0;
        for(String log : logs){
            String[] strs = log.split(":");
            int id = Integer.parseInt(strs[0]);
            int time = Integer.parseInt(strs[2]); 
            if(!stack.isEmpty()) res[stack.peek()] += time - prev;
            prev = time;
            if(strs[1].equals("start")){
                stack.push(id);      
            }else{
                res[stack.pop()]++; //注意因为是1秒区间 所以要加1
                prev++;
            }
        }
        return res;     
    }
}