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package com.yangchd.leetcode.easy;

/**

* @author yangchd 2018/4/17.

*

* 9. Palindrome Number

* Determine whether an integer is a palindrome. An integer is a palindrome when it reads the same backward as forward.

*

* Example 1:

* Input: 121

* Output: true

*

* Example 2:

* Input: -121

* Output: false

* Explanation: From left to right, it reads -121. From right to left, it becomes 121-. Therefore it is not a palindrome.

*

* Example 3:

* Input: 10

* Output: false

* Explanation: Reads 01 from right to left. Therefore it is not a palindrome.

*

* Follow up:

* Coud you solve it without converting the integer to a string?

*/

public class PalindromeNumber {

class Solution {

/**

* 这个是转成String进行校验

*/

public boolean isPalindrome(int x) {

if (x == 0) {

return true;

}

if (x < 0) {

return false;

}

String str = String.valueOf(x);

int length = str.length();

for (int i = 0; i < (length - i - 1); i++) {

if (str.charAt(i) != str.charAt(length - i - 1)) {

return false;

}

}

return true;

}

/**

* 不用转换成String，转换一半，然后两边相比较

*/

public boolean solutionOne(int x) {

if (x < 0 || (x != 0 && x % 10 == 0)) {

return false;

}

int rev = 0;

while (x > rev) {

rev = rev * 10 + x % 10;

x = x / 10;

}

return (x == rev || x == rev / 10);

}

}

}