数字在排序数组中出现的次数

题目描述

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 len= data.size();
        if (len == 0)
            return 0;
        bool find = 0;
        int begin = 0,end = len -1,mid;
        while(begin <= end)
        {
            mid = (begin + end)/2;
            if(data[mid] > k)
            {
                end = mid - 1;
            }
            else if(data[mid] < k)
            {
                begin = mid + 1;
            }
            else
            {
                find = 1;
                break;
            }
        }
        if(!find)
            return 0;
        
        int cnt = 1;
        int i = mid + 1;
        while(i < len && data[i] == k)
        {
            ++ cnt;
            ++i;
        }
        i = mid - 1;
        while(i >=0 && data[i] == k)
        {
            ++ cnt;
            --i;
        }
        return cnt;
    }
};