Palindrome Number

最新推荐文章于 2024-10-27 22:09:20 发布

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最新推荐文章于 2024-10-27 22:09:20 发布

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原文链接：http://www.cnblogs.com/wylwyl/p/10412309.html

本文介绍了一种高效判断整数是否为回文数的算法，通过比较首尾数字并逐步去除两端数字的方式，无需额外空间，适用于各种整数大小。文章提供了详细的代码实现，并解释了算法的工作原理。

题目：

Determine whether an integer is a palindrome. Do this without extra space

解答：

First, compare the first and last
digit. If they are not the same, it must not be a palindrome. If they are the same, chop off
one digit from both ends and continue until you have no digits left, which you conclude
that it must be a palindrome

 1 public boolean isPalindrome(int x) {
 2     if(x < 0) {
 3         return false;
 4     }
 5 
 6     int div = 1;
 7     while(x / div >= 10) {
 8         div = div * 10;
 9     }
10 
11     while(x != 0) {
12         int l = x / div;
13         int r = x % 10;
14         if(l != r) {
15             return false;
16         }
17 
18         x = (x % div) / 10;
19         div = div / 100;
20     }
21 
22     return true;
23 }