LeetCode 刷题之 Reverse Integer

LeetCode 刷题之 Reverse Integer

/**
 * @Time : 19/03/2018 10:18
 * @Author : lotus
 * @File : ReverseInteger.java
 * @Software: IntelliJ IDEA
 * @Desc :
 * @license : Copyright(C), Alex
 * @Contact : alex.cs.monash@gmail.com
 */

import java.util.Scanner;

/**
 * Question 7: Reverse Integer
 * <p>
 * Given a 32-bit signed integer, reverse digits of an integer.
 * Example 1:
 * Input: 123
 * Output:  321
 * <p>
 * Example 2:
 * Input: -123
 * Output: -321
 * <p>
 * Example 3:
 * Input: 120
 * Output: 21
 * <p>
 * Note:
 * Assume we are dealing with an environment which could only hold integers within the 32-bit signed integer range.
 * For the purpose of this problem, assume that your function returns 0 when the reversed integer overflows.
 */
public class ReverseInteger {

    public int reverse(int x) {
        long result = 0;
        while (x != 0) {
            result = result * 10 + x % 10;
            x /= 10;
        }

        if (result > Integer.MAX_VALUE || result < Integer.MIN_VALUE) {
            return 0;
        }
        return (int) result;
    }

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int input = scanner.nextInt();

        ReverseInteger reverseInteger = new ReverseInteger();
        System.out.println(reverseInteger.reverse(input));
    }
}