小练习：Two Sum

1.example

Given nums = [2, 7, 11, 15], target = 9,

Because nums[0] + nums[1] = 2 + 7 = 9,
return [0, 1].

2.solve

class Solution {
public:
    vector<int> twoSum(vector<int>& nums, int target) {
         std::vector<int>temp;
        for(int i = 0;i<nums.size();++i)
        {
            for(int j = i+1;j<nums.size();++j)
            {
                if((nums[i]+nums[j])==target)
                {
                     temp.push_back(i);
                     temp.push_back(j);
                     return temp;
                }
            }
        }
    }
};