In the context of number theory and computer science, a palindrome number is typically defined as an integer that remains the same when its digits are reversed.

For positive integers like 121, the reversed form is still 121, satisfying the palindrome condition.

However, for negative numbers such as -121, reversing the digits produces 121-, which is neither a valid number nor equivalent to the original input.

Technically, negative numbers are not considered palindromic under the standard mathematical definition, primarily because of the presence of the negative sign and the fact that the reversed form isn’t a valid integer representation.

In most programming problems (e.g., LeetCode, technical interviews), negative numbers are explicitly treated as non-palindromic by default.

When implementing a function to check if an integer is a palindrome, is it best practice to immediately return false for any negative input? Or are there contexts where treating -121 as a palindrome is acceptable?

Interested in hearing your views, especially if you’ve seen exceptions in real-world codebases or specific algorithmic challenges.