Reverse Integer | LeetCode

Here are some good questions to ask before coding. Bonus points for you if you have already thought through this!

If the integer‘s last digit is 0, what should the output be? ie, cases such as 10, 100.

Did you notice that the reversed integer might overflow? Assume the input is a 32-bit integer, then the reverse of 1000000003 overflows. How should you handle such cases?

Throw an exception? Good, but what if throwing an exception is not an option? You would then have to re-design the function (ie, add an extra parameter).

Java:

public class Solution {
    public int reverse(int x) {
       int a,rem,result=0;
       a = Math.abs(x);
       while(a != 0)
       {
           rem = a % 10;
           result = result * 10 + rem;
           a /= 10;
       }
       if(x < 0)
         return -result;
       else return result;
    }
}

      本题直接使用一个int型变量result保存最后的结果，这样可能会有结果溢出的情况，也可以使用Queue<Integer>来保存最后的结果，保持完毕后需要把各数值全部加起来，作为返回的结果。