오답 확인 부탁드립니다.

import java.time.Year;
import java.util.*;
class Main {
    public static int solution(int N, int M, int[] arr) {
        int answer = 0;
        for (int lt = 0; lt < N; lt++) {
            int sum = 0;
            int rt = lt;
            while (sum < M) {
                sum += arr[rt];
                rt++;
                if (rt >= N) break;
                if (sum == M) {
                    answer++;
                }
            }
        }

        return answer;
    }

    public static void main(String[] args){
        Scanner kb = new Scanner(System.in);

        int N = kb.nextInt();
        int M = kb.nextInt();
        int[] arr = new int[N];

        for (int i = 0; i < N; i++) {
            arr[i] = kb.nextInt();
        }

        System.out.println(solution(N, M, arr));

    }
}

오답이 나와 확인해봤습니다.답이 1씩 낮아서 확인해보았는데(테스트의 N=100, M=100 지점), answer가 1씩 낮았습니다.답지와 제코드의 결과값을 비교해보았는데 너무 다른 양상이 나와 질문합니다. 

답지

answer: 18 lt: 50 rt: 83 sum: 100

answer: 19 lt: 53 rt: 86 sum: 100

answer: 20 lt: 55 rt: 88 sum: 100

answer: 21 lt: 58 rt: 91 sum: 100

answer: 22 lt: 60 rt: 93 sum: 100

answer: 23 lt: 65 rt: 99 sum: 100

제 코드

answer: 16 lt: 46 rt: 77 sum: 100

answer: 17 lt: 49 rt: 83 sum: 100

answer: 18 lt: 50 rt: 84 sum: 100

answer: 19 lt: 53 rt: 87 sum: 100

answer: 20 lt: 55 rt: 89 sum: 100

answer: 21 lt: 58 rt: 92 sum: 100

answer: 22 lt: 60 rt: 94 sum: 100

어디가 잘못된걸까요?

import java.util.*;
class Main {
    public int solution(int N, int M, int[] arr) {
        int answer = 0;
        for (int lt = 0; lt < N; lt++) {
            int sum = 0;
            int rt = lt;
            while (sum < M) {
                sum += arr[rt];
		if (sum == M) {
                    answer++;
                }
                rt++;
                if (rt >= N) break;  
            }
        }

        return answer;
    }

    public static void main(String[] args){
        Scanner kb = new Scanner(System.in);
		Main T = new Main();

        int N = kb.nextInt();
        int M = kb.nextInt();
        int[] arr = new int[N];

        for (int i = 0; i < N; i++) {
            arr[i] = kb.nextInt();
        }

        System.out.println(T.solution(N, M, arr));

    }
}