BOI 2013 P2 - Palindrome-Free Numbers

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Points: 15 (partial)
Time limit: 1.0s
Memory limit: 128M

Problem type

A string is a palindrome if it remains the same when it is read backwards. A number is palindromefree if it does not contain a palindrome with a length greater than 1 as a substring. For example, the number 16276 is palindrome-free whereas the number 17276 is not because it contains the palindrome 727.

Your task is to calculate the total number of palindrome-free numbers in a given range.


The input contains two integers, a and b.


The output should contain one integer: the total number of palindrome-free numbers in the range a, \dots , b (including a and b).


0 \le a \le b \le 10^{18}

In test cases worth 25 points: b - a \le 100\,000.

Sample Input 1

123 321

Sample Output 1


Sample Input 2

123456789 987654321

Sample Output 2



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