leetcode357

public class Solution {
    public int CountNumbersWithUniqueDigits(int n) {
        if (n == )
            {
                return ;
            }
            int res = ;
            int uniqueDigits = ;
            int availableNumber = ;
            while (n-- >  && availableNumber > )
            {
                uniqueDigits = uniqueDigits * availableNumber;
                res += uniqueDigits;
                availableNumber--;
            }
            return res;
    }
}

https://leetcode.com/problems/count-numbers-with-unique-digits/#/description