LeetCode() Search for a Range

class Solution {
public:
    vector<int> searchRange(vector<int>& nums, int target) {
        vector<int> res;
        vector<int> xxx;
        xxx.push_back(-1);
        xxx.push_back(-1);
        int left=0,right=nums.size()-1;
        while(left<=right)
        {
            int mid=(right+left)/2;
            if(nums[mid]>target)
                right=mid-1;
            else if(nums[mid] < target)
                left=mid+1;
            else
            {
                int t=mid;
                while(t>=0 && nums[t]==target)
                    t--;
                res.push_back(t+1);
                while(mid<=right && nums[++mid] == target)
                    ;
                res.push_back(mid-1);
				return res;
            }
        }
        
        return xxx;
    }
};