LeetCode: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].

class Solution {
public:
    vector<int> searchRange(int A[], int n, int target) {
        vector<int> res={-1,-1};
        for(int i=0;i<n;i++)
        {
            if(target==A[i])
            {
                res[0]=i;
                while(i+1<n&&target==A[i+1])
                    i++;
                res[1]=i;
                break;
            }
        }
        return res;
    }
};