[LeetCode]Reverse Integer解题报告

[题目描述]

Reverse digits of an integer.

Example1: x = 123, return 321
Example2: x = -123, return -321

click to show spoilers.

Have you thought about this?

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).

[解题思路]

整数反转也比较常见，一般的作法是把整数从末尾开始，一位一位的移动逐位生成咱们所需的新数。

class Solution {
public:
    int reverse(int x) {
        // Start typing your C/C++ solution below
        // DO NOT write int main() function
        int nReverse = 0;
        while (x != 0) {
            nReverse = nReverse * 10 + x % 10;
            x = x / 10;
        }
        return nReverse;
    }
};

[源代码]

https://github.com/rangercyh/leetcode/blob/master/Reverse%20Integer