Q930和相同的二元子数组

输入：A = [1,0,1,0,1], S = 2
输出：4
解释：
如下面黑体所示，有 4 个满足题目要求的子数组：
[1,0,1,0,1]
[1,0,1,0,1]
[1,0,1,0,1]
[1,0,1,0,1]

class Solution {
    public int numSubarraysWithSum(int[] A, int S) {
        int sum = 0;
        int result = 0;
        HashMap map = new HashMap<>();
        map.put(0, 1);

        for (int i : A) {
            sum += i;
            result += map.getOrDefault(sum - S, 0);
            int t = map.getOrDefault(sum, 0) + 1;
            map.put(sum, t);
        }

        return result;
    }
}