求1+2+3+...+n_JAVA_中等

// 递归处理可以累加，与操作可以代替if

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