Q7：Reverse Integer

7. Reverse Integer

官方的链接：7. Reverse Integer

Description ：

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

Example1:

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Input: 123

Output: 321

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Example2:

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Input: -123

Output: -321

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Example3:

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Input: 120

Output: 21

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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.

问题描述

反转32位的数字

思路

上一次的模*10 + 这一次的模。中间判断是否有溢出

注意：last_mod * 10 + this_mod，而x /= 10

[github-here]

 public class Q7_ReverseInteger {
     public int reverse(int x) {
         int revResult = 0;
         while (0 != x){
             int newResult = revResult * 10 + x % 10;
             //judge whether it overflows
             if (newResult / 10 != revResult) {
                 return 0;
             }
             revResult = newResult;
             x /= 10;
         }
         return revResult;
     }
 }