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Palindrome Number

时间:2017-05-12 20:13:53      阅读:200      评论:0      收藏:0      [点我收藏+]

标签:div   rest   eric   cas   however   public   ext   回文字符串   determine   

题目

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

Some hints:

Could negative integers be palindromes? (ie, -1)

If you are thinking of converting the integer to string, note the restriction of using extra space.

You could also try reversing an integer. However, if you have solved the problem "Reverse Integer", you know that the reversed integer might overflow. How would you handle such case?

There is a more generic way of solving this problem.

方法

和回文字符串的推断类似,仅仅须要比較相应的位是否同样。
	    public boolean isPalindrome(int x) {
             if (x < 0) return false;
              int div = 1;
              while (x / div >= 10) {
                div *= 10;
              }        
              while (x != 0) {
                int l = x / div;
                int r = x % 10;
                if (l != r) return false;
                x = (x % div) / 10;
                div /= 100;
              }
              return true;
	    }


Palindrome Number

标签:div   rest   eric   cas   however   public   ext   回文字符串   determine   

原文地址:http://www.cnblogs.com/cxchanpin/p/6846980.html

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