[백준] 2559번 수열 (silver 3

import java.io.*;
import java.util.*;

public class Main{
    public static void main(String[] args) throws IOException{
        BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
        BufferedWriter bw=new BufferedWriter(new OutputStreamWriter(System.out));
        StringTokenizer st=new StringTokenizer(br.readLine());
        int n=Integer.parseInt(st.nextToken());
        int k=Integer.parseInt(st.nextToken());
        int max=-100*k;
        int temp=0;
        int[] num=new int[n];
        st=new StringTokenizer(br.readLine());
        for(int i=0; i<k; i++){
            num[i]=Integer.parseInt(st.nextToken());
            temp+=num[i];
        }
        max= max < temp ? temp : max;
        for(int i=k; i<n; i++){
            num[i]=Integer.parseInt(st.nextToken());
            temp+=num[i]-num[i-k];
            max = max < temp ? temp : max;
        }
        bw.write(max+"");
        bw.flush();
    }
}