leetcode

0 class Solution {

1 public:

2 int findSpecialInteger(vector<int> &arr) {

3 const int n = size(arr), quarter = n / 4;

4 for (const int candidate : {arr[n / 4], arr[n / 2], arr[3 * n / 4]}) {

5 const int left = lower_bound(begin(arr), end(arr), candidate) - begin(arr);

6 const int right = upper_bound(begin(arr), end(arr), candidate) - begin(arr);

7 if (right - left > quarter) return candidate;

8 }

9 return -1;

10 }

11 };