题目链接：https://leetcode-cn.com/problems/find-three-consecutive-integers-that-sum-to-a-given-number/
题目如下：

class Solution {
public:
    vector<long long> sumOfThree(long long num) {
        //结论：如果num是3的倍数，返回num/3-1、num/3、num/3+1，否则返回空数组
        if(num%3==0) return {num/3-1,num/3,num/3+1};
        else return {};
    }
};