数字在排序数组中出现的次数.txt

//统计一个数字在排序数组中出现的次数。 
class Solution {
public:
    int GetNumberOfK(vector<int> data ,int k) {
        int size = data.size();
        if(size == 0)return 0;
        
        int left = getleft(data,k);
        int right = getright(data,k);
        
        return right-left+1;
    }
    
    int getleft(vector<int>data,int k)
    {
        int start=0,end = data.size()-1;
        int mid = start+(end-start)/2;
        while(start<=end)
        {
            if(data[mid]<k)start=mid+1;
            else
            {
                end = mid-1;
            }
            mid = start+(end-start)/2;
        }
        
        return start;
    }
    int getright(vector<int>data,int k)
    {
        int start=0,end = data.size()-1;
        int mid = start+(end-start)/2;
        while(start<=end)
        {
            if(data[mid]<=k)start=mid+1;
            else
            {
                end = mid-1;
            }
            mid = start+(end-start)/2;
        }
        
        return end;
    }
};