[LeetCode] 087: Reverse Integer

最新推荐文章于 2021-01-09 00:40:58 发布

1.02^365的成长裂变

最新推荐文章于 2021-01-09 00:40:58 发布

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本文介绍了一种反转整数的算法实现，通过示例展示如何将整数如123转换为321，并考虑了负数及溢出等特殊情况的处理。提供了完整的C++代码实现。

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[Problem]

Reverse digits of an integer.

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

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).

[Solution]

class Solution {
public:
	int reverse(int x) {
		// Note: The Solution object is instantiated only once and is reused by each test case.
		long long y = 0;
		bool mark = x < 0 ? true, x = -1*x : false;
		while(x > 0){
			y = y*10 + x%10;
			x /= 10;
		}
		return mark ? -y : y;
	}
};