658. Find K Closest Elements

class Solution {
public:
    int helper(int left, int right, const vector<int>& arr, int x)
    {
        if (x < arr[0]) return 0;
        if (x > arr[arr.size() - 1]) return arr.size() - 1;

        int mid = left + (right - left) / 2;
        if (arr[mid] == x)
        {
            return mid;
        }
        else if (arr[mid] > x)
        {
            if (mid - 1 >= 0 && arr[mid - 1] < x)
            {
                return abs(x - arr[mid - 1]) < abs(x - arr[mid]) ? mid - 1 : mid;
            }
            return helper(left, mid - 1, arr, x);
        }
        else
        {
            if (mid + 1 < arr.size() && arr[mid + 1] > x)
            {
                return abs(x - arr[mid + 1]) < abs(x - arr[mid]) ? mid + 1: mid;
            }
            return helper(mid + 1, right, arr, x);
        }
    }

    vector<int> findClosestElements(vector<int>& arr, int k, int x) {
        int pos = helper(0, arr.size(), arr, x);

        vector<int> result;
        result.reserve(k);

        int i = pos;
        int j = pos + 1;

        while (result.size() < k)
        {
            if (i >=0 && j <arr.size())
            {
                if (abs(x - arr[i]) <= abs(x - arr[j]))
                {
                    result.push_back(arr[i]);
                    i--;
                }
                else
                {
                    result.push_back(arr[j]);
                    j++;
                }
            }
            else if (i >= 0)
            {
                result.push_back(arr[i]);
                i--;
            }
            else
            {
                result.push_back(arr[j]);
                j++;
            }
        }

        // todo is should be more efficient somehow
        sort(result.begin(), result.end());
        return result;
    }
};