java中时间复杂度的hackathon代码段

昨天我参加了hackathon，但无法通过时间复杂度，但观看了一些视频，但无法获得它。应修改哪些代码以通过复杂度错误。请有人帮助，提前感谢

Constraints
    2<=N<=3*10^5 
    0<=k<=3*10^5
    1<=Li<=10^9 **Li is list value**

Input N=5 k = 2;
List values [10,4,7,2,1] 
Output = 19

public TestClass{
       public static void main(String[] args) throws Exception {
              BufferReader br = new BufferReader(new InputStreamReader(System.in));
              String[] str = br.readLine();
              int n = Integer.parseInt(str[0]);
              int k = Integer.parseInt(str[1]);
              List<Integer> list = new LinkedList<Integer>(); **should i use ArrayList here**
              String[] str2 = br.readLine().split(" ");
              for(int i=0;i<n;i++){
                  list.add(Integer.parseInt(str2[i]));
              }
              for(int j=0;j<k;j++){
                  list.set(list.indexOf(Collections.max(list)),(int)Math.round((double)Collection.max(list)/2)); **replacing max list postion with max/2**
                  list.set(list.indexOf(Collections.min(list)), Collections.min(list)*2);
              }
        System.out.println(list.stream().reduce(0,Integer::sum)); **summing the list**
      }
}

约束
2.