使用二分

# -*- coding:utf-8 -*-
class Solution:
    def GetNumberOfK(self, data, k):
        # write code here
        count = 0
        if len(data)==0:
            return 0
        index = self.binaryquery(data,k)
        if index == -1:
            return 0
        cur = index
        while cur < len(data) and data[cur]==k:
            count += 1
            cur += 1
        cur = index
        while cur >= 0 and data[cur]==k:
            count += 1
            cur -= 1
        return count-1
    
    
    def binaryquery(self,data,k):
        l = len(data)
        m = l//2
        a = -1
        b = -1
        if m==0 and data[m] != k:
            return -1
        if data[m] == k:
            return m
        elif k > data[m]:
             a = self.binaryquery(data[:m:-1],k)
        else:
             b = self.binaryquery(data[:m],k)
        if a>b:
            return a
        else:
            return b