문제

풀이

• 투포인터 기본 문제

코드

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));

        StringTokenizer st=new StringTokenizer(br.readLine());
        int n=Integer.parseInt(st.nextToken());
        int k=Integer.parseInt(st.nextToken());
        st=new StringTokenizer(br.readLine());
        int[] nums=new int[n];
        for(int i=0;i<n;i++)nums[i]=Integer.parseInt(st.nextToken());

        int l=0;
        int r=0;
        int cnt=1;
        int sum=nums[0];
        int ans=Integer.MIN_VALUE;
        while(l<=r){
            if(r==n)break;
            if(cnt<=k){
                if(cnt==k)ans=Math.max(ans,sum);
                cnt++;
                ++r;
                if(r<n)sum+=nums[r];
            }
            else{
                cnt--;
                sum-=nums[l++];
            }
        }
        System.out.println(ans);
    }
}

#투포인터