[LeetCode] Problem 7 - Reverse Integer

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Given a 32-bit signed integer, reverse digits of an integer.

Example

No.1

Input: 123

Output: 321

No.2

Input: -123

Output: -321

No.3

Input: 120

Output: 21

Note

Assume we are dealing with an environment which could only store integers within the 32-bit signed integer range: [−2^31, 2^31 − 1]. For the purpose of this problem, assume that your function returns 0 when the reversed integer overflows.

Code

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public int reverse(int x) {
    int reverseX = 0;

    while (x != 0) {
        if (Math.abs(reverseX) > Integer.MAX_VALUE / 10)
            return 0;

        reverseX = reverseX * 10 + x % 10;
        x /= 10;
    }

    return reverseX;
}