Use a binary search as usual with an extra linear scan for the range when it finds the target.

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