题解 | #数字在升序数组中出现的次数#

1. 只要找到重复数字的左边界。之后迭代判断即可。

class Solution {
public:
    int GetNumberOfK(vector<int> data ,int k) {

        if(!data.size()) return 0; 

        int res = 0;

        int left = 0;
        int right = data.size()-1;

        while(left<right){
            int mid = (left+right)/2;

            if(data[mid]==k){
               right = mid;
            }else if(data[mid]<k){
                left = mid + 1;
            }else{
               right = mid;
            }
        }

        for(;left< data.size();left++){

            if(data[left]==k) res++;

        }

        return res;



    }
};