解题思路:二分查找最强模板
class Solution {
public:
vector<int> searchRange(vector<int>& nums, int target){
if(nums.empty()) return {-1,-1};
int l=0,r=nums.size()-1;
while(l<r){
int mid=l+(r-l)/2;
if(nums[mid]<target) l=mid+1;
else r=mid;
}
if(nums[r]!=target) return {-1,-1};
int start=r;
l=0,r=nums.size()-1;
while(l<r){
int mid=l+(r-l+1)/2;
if(nums[mid]>target) r=mid-1;
else l=mid;
}
if(nums[r]!=target) return {-1,-1};
int end=l;
return {start,end};
}
};