题解 | #数字在升序数组中出现的次数#

class Solution { public: int GetNumberOfK(vector data ,int k) { int l = 0, r = data.size() - 1; if(data.empty()) return 0; //寻找上届和下届 while(l < r) { int mid = l + r >> 1; if(data[mid] >= k) { r = mid; } else { l = mid + 1; } } if(data[l] != k) return 0; int ans1 = l; l = 0, r = data.size() - 1;

    while(l < r)
    {
        int mid = l + r + 1 >> 1;
        if(data[mid] <= k)
        {
            l = mid;
        }
        else
        {
            r = mid - 1;
        }
    }
    return l - ans1 + 1;
}

};