class Solution {
public:
    int getNumberOfK(vector<int>& nums , int k) {
        while(!nums.empty()){   //动态数组nums为空的时候返回ture,nums不为空的时候返回false
            if(nums.back()==k)
            count++;
            nums.pop_back();
        }
        return count;
    }
    int count;
};