leetcode 二分查找 Search for a Range

Search for a Range

Given a sorted array of integers, find the starting and ending position of a given target value.

Your algorithm's runtime complexity must be in the order of O(log n).

If the target is not found in the array, return [-1, -1].

For example,
Given [5, 7, 7, 8, 8, 10] and target value 8,
return [3, 4].

vector
  
    searchRange(int A[], int n, int target){
	int l = distance(A, lower_bound(A, A + n, target));
	int u = distance(A, upper_bound(A, A + n, target));
	vector
   
     res; if(A[l] != target){ res.push_back(-1); res.push_back(-1); }else{ res.push_back(l); res.push_back(u - 1); } return res; }