Package g0701_0800.s0788_rotated_digits

Class Solution

java.lang.Object
g0701_0800.s0788_rotated_digits.Solution
public class Solution extends java.lang.Object
788 - Rotated Digits.

Medium

An integer x is a good if after rotating each digit individually by 180 degrees, we get a valid number that is different from x. Each digit must be rotated - we cannot choose to leave it alone.

A number is valid if each digit remains a digit after rotation. For example:

  • 0, 1, and 8 rotate to themselves,
  • 2 and 5 rotate to each other (in this case they are rotated in a different direction, in other words, 2 or 5 gets mirrored),
  • 6 and 9 rotate to each other, and
  • the rest of the numbers do not rotate to any other number and become invalid.

Given an integer n, return the number of good integers in the range [1, n].

Example 1:

Input: n = 10

Output: 4

Explanation:

 There are four good numbers in the range [1, 10] : 2, 5, 6, 9.
 Note that 1 and 10 are not good numbers, since they remain unchanged after rotating.

Example 2:

Input: n = 1

Output: 0

Example 3:

Input: n = 2

Output: 1

Constraints:

  • 1 <= n <= 104

  • Constructor Summary

    Constructors
    Constructor
    Description
    Solution()
     

  • Method Summary

    Modifier and Type
    Method
    Description
    int
    rotatedDigits(int n)
     

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • Constructor Details

    • Solution

      public Solution()

  • Method Details

    • rotatedDigits

      public int rotatedDigits(int n)