题解 | #未排序正数数组中累加和为给定值的最长子数组的长度#

class Main07Test {
    public int help(int[] arr, int n, int target) {
        int left = 0, right = 0;
        int windowSum = arr[0];
        int maxLen = 0;
        while (right < n - 1) {
            // 扩窗
            // if (arr[right] > target) break; // 剪枝
            right++; // 一开始会加一
            windowSum += arr[right];
            // 缩窗
            while (left <= right && windowSum > target) {
                windowSum -= arr[left];
                left++;
            }
            // 符合条件
            if (left <= right && windowSum == target) {
                maxLen = Math.max(maxLen, right - left + 1);
                windowSum -= arr[left];
                left++;
            }
        }
        return maxLen;
    }
}


public class Main {
    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        String[] strings = br.readLine().split(" ");
        int n = Integer.parseInt(strings[0]);
        int target = Integer.parseInt(strings[1]);
        int[] arr = new int[n];
        // 每次读行
        String[] strs = br.readLine().split(" ");
        for (int i = 0; i < n; i++) {
            arr[i] = Integer.parseInt(strs[i]);
        }
        Main07Test test = new Main07Test();
        int help = test.help(arr, n, target);
        System.out.println(help);
    }
}