Class Solution


  • public class Solution
    extends Object
    2376 - Count Special Integers.

    Hard

    We call a positive integer special if all of its digits are distinct.

    Given a positive integer n, return the number of special integers that belong to the interval [1, n].

    Example 1:

    Input: n = 20

    Output: 19

    Explanation: All the integers from 1 to 20, except 11, are special. Thus, there are 19 special integers.

    Example 2:

    Input: n = 5

    Output: 5

    Explanation: All the integers from 1 to 5 are special.

    Example 3:

    Input: n = 135

    Output: 110

    Explanation: There are 110 integers from 1 to 135 that are special.

    Some of the integers that are not special are: 22, 114, and 131.

    Constraints:

    • 1 <= n <= 2 * 109
    • Constructor Detail

      • Solution

        public Solution()
    • Method Detail

      • countSpecialNumbers

        public int countSpecialNumbers​(int n)