[LeetCode]007. Reverse Integer

发布时间:2017-3-24 21:58:53 编辑:www.fx114.net 分享查询网我要评论
本篇文章主要介绍了"[LeetCode]007. Reverse Integer",主要涉及到[LeetCode]007. Reverse Integer方面的内容,对于[LeetCode]007. Reverse Integer感兴趣的同学可以参考一下。

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: use the math method to reverse the order,  result = result*10 + left; the + operation in the while loop can eliminate the redundant 0; such as “500--->5 (which is '0+0+5')"; use the Math.abs() method to get the abstract value, because the module on negative number has ambiguity.(different languages have different results). 负数取模有争议,不同的编程语言给出的结果不同,参见 http://ceeji.net/blog/mod-in-real/ 实数范围内的求模(求余)运算:负数求余究竟怎么求 java里表示整数最大值Integer.MAX_VALUE  (2^31 -1); public class Solution { public int reverse(int x) { // Start typing your Java solution below // DO NOT write main() function int flag = 1; if(x<0){ flag = -1; } int temp = Math.abs(x); int left = 0; int result = 0; while(temp != 0){ left = temp % 10; result = result*10 + left; temp = temp/10; } if(result > Integer.MAX_VALUE){ return -1; // only return -1 here, or we can print one message //or use a static field variable "isValid" for representint states? }else{ return result*flag; } } }

上一篇:HTML5 App实战(7):连连看
下一篇:CreateBitmap

相关文章

相关评论

本站评论功能暂时取消,后续此功能例行通知。

一、不得利用本站危害国家安全、泄露国家秘密,不得侵犯国家社会集体的和公民的合法权益,不得利用本站制作、复制和传播不法有害信息!

二、互相尊重,对自己的言论和行为负责。

好贷网好贷款