#include <iostream>
#include <vector>
using namespace std;

int GetNumberOfK(vector<int> data ,int k){
	int len=data.size();
	if(len==0) return 0;
	int low=0;
	int high=len-1;
	int mid;
	while(low<high){
		mid=(low+high)/2;
		if(data[mid]==k)
			break;
		else{
			if(data[mid]<k){
				low=mid+1;
			}else{
				high=mid-1;
			}
		}
	}
	mid=(low+high)/2;
	if(data[mid]!=k) return 0;
	int sum=1;
	int i=mid-1;
	while(i>=0&&data[i]==k){
		sum++;
		i--;
	}
	i=mid+1;
	while(i<len&&data[i]==k){
		sum++;
		i++;
	}
	return sum;
}

int main(){
	//int a[10]={1,2,3,3,3,4,5,6,8,8};
	int a[6]={3,3,3,3,4,5};
	vector<int> vec(a,a+6);
	cout<<GetNumberOfK(vec,3)<<endl;
	system("pause");
}