H-Index II LeetCode solution in C++

1
class Solution {
2
 public:
3
  int hIndex(vector<int> &citations) {
4
    int start = 0, end = citations.size() - 1;
5
    int n = citations.size();
6
    while (start <= end) {
7
      int mid = start + (end - start) / 2;
8
      int val = citations[mid];
9
      if (val == (n - mid))
10
        return citations[mid];
11
      else if (val < n - mid) {
12
        start = mid + 1;
13
      } else {
14
        end = mid - 1;
15
      }
16
    }
17
    return n - start;
18
  }
19
};