第5课：循环枚举（子序列枚举2）

int a[10000];
int main() {
    int n, k;
    cin >> n >> k;
    for (int i = 1; i <= n; i++) {
        cin >> a[i];
    }
    for (int i = 1; i <= n; i++) {
        int s = 0;  
        for (int j = i; j <= n; j++) {  //若需前后比较，则可令s = a[i];  j = i + 1
            s = s + a[j];
            if (s > k)
                break;
            if (s == k) {
                cout << "yes";
                return 0;
            }
        }
    }
    cout << "no";
    return 0;
}