A Number After a Double Reversal — LeetCode 2119 Python Solution

The problem

Reversing an integer means to reverse all its digits. For example, reversing 2021 gives 1202.

Example

Input

num = 526

Output

true

Explanation

Reverse num to get 625, then reverse 625 to get 526, which equals num.

Python solution

class Solution:
    def isSameAfterReversals(self, num: int) -> bool:
        return num == 0 or num % 10 != 0

Complexity

Pattern: Math and Number Theory

Find the closed form, the invariant, or the modular identity — and skip the loop entirely. LeetCode 2119. A Number After a Double Reversal is filed here on both counts: the reference solution below belongs to the algorithm family this hub collects, and LeetCode tags it Math.

The math and number theory guide has the Python template for the pattern and the 485 LeetCode problems that use it.

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