LeetCode - Refresh - Search for a Range

Actually, we are searching the right end of the target so:

1. start could be same as end

2. A[mid] > target, shift to left

3. A[mid] <= target shift to right

class Solution {
public:
    int bsearch(int A[], int start, int end, int target) {
        int index = -1, mid = 0;
        while (start <= end) {
            mid = (start + end)/2;
            if (A[mid] <= target) {
                start = mid + 1;
                index = mid;
            } else {
                end = mid - 1;
            }
        }
        return index;
    }
    vector<int> searchRange(int A[], int n, int target) {
        vector<int> result(2, -1);
        result[0] = bsearch(A, 0, n-1, target-1) + 1;
        result[1] = bsearch(A, 0, n-1, target);
        if (result[0] == -1 || A[result[0]] != target) {
            return vector<int> (2, -1);
        }
        return result;
    }
};