백준 JAVA 2003 수들의 합2

https://www.acmicpc.net/problem/2003

2003번: 수들의 합 2

 

 

package BAEKJOON.Silver.Ⅳ;

import java.util.Scanner;

public class NO2003_2 {
    public static void main(String[] args) {

        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int m = sc.nextInt();

        int[] arr = new int[n];
        for (int i = 0; i < n; i++) {
            arr[i] = sc.nextInt();
        }

        int start = 0;
        int end = 0;
        int sum = 0;
        int count = 0;

        while( start < n) {
            if( sum > m || end == n) {
                sum = sum - arr[start];
                start++;
            } else {
                sum = sum + arr[end];
                end++;
            }

            if ( sum == m) {
                count++;
            }
        }
        System.out.println(count);

    }
}