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:
Given an integer n, return the number of good integers in the range [1, n].
Examples
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
788. Rotated Digits
Medium
30 Points
Math
Dynamic Programming
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:
Given an integer n, return the number of good integers in the range [1, n].
Examples
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.