问题链接

Reverse Integer | LeetCode OJ

问题描述

反转一个整数

例一: x = 123, 返回 321
例二: x = -123, 返回 -321

解决方法

public class Solution {
    public int reverse(int x) {
        int absNumber = Math.abs(x);
        if(absNumber > 0 && absNumber < 10){
            return x;
        }
        String numberString = Integer.toString(absNumber);
        if(numberString.indexOf("-") == 0){
            numberString = numberString.substring(1);
        }
        String reverseNumberString = "";
        int lastPosition = numberString.length()-1;
        for(int i = lastPosition;i>=0;i--){
            String a = String.valueOf(numberString.charAt(i));
            if(!(a.equals("0") && reverseNumberString.equals(""))){
                reverseNumberString += a;
            }
        }
        try{
            int reverseNumber = Integer.parseInt(reverseNumberString);
            if(x<0){
                return -reverseNumber;
            }
            return reverseNumber;
        }catch(NumberFormatException e){
            return 0;
        }
    }
}