Here is my c++ code. Sometimes it says compile error, yet sometimes it says accepted. Not understand why. Can anyone help? Thanks a lot!

```
class Solution {
public:
int threeSumSmaller(vector<int>& nums, int target) {
if(nums.size()<3) return 0;
int result = 0;
sort(nums.begin(),nums.end());
for(int i=0;i<nums.size();i++){
int left = i+1, right = nums.size()-1;
while(left<right){
if((nums[i]+nums[left]+nums[right])<target){
result = result + right-left;
left++;
}
else
right--;
}
}
return result;
}
};
```