34题

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