数字在排序数组中出现的次数

统计一个数字在排序数组中出现的次数。

二分找n和n+1

class Solution {
public:
    int bin_search(const vector<int> &data, const int k)
    {
        int left = 0, right = data.size();
        while (left < right)
        {
            const int mid = (left + right) / 2;
            if (data[mid] > k)
            {
                right = mid;
            }
            else if (data[mid] == k)
            {
                right = mid;
            }
            else
            {
                left = mid + 1;
            }
        }
        return left;
    }
    int GetNumberOfK(vector<int> data ,int k) {
        int left = bin_search(data, k);
        int right = bin_search(data, k + 1);
        return right - left;
    }
};