解法一：或

public class Solution {
    public int Sum_Solution(int n) {
        boolean flag=(n==1)||((n+=Sum_Solution(n-1))>0);
        return n;
    }
}

解法二：与

public class Solution {
    public int Sum_Solution(int n) {
        boolean flag=(n>1)&&((n+=Sum_Solution(n-1))>0);
        return n;
    }
}